OPEN PRICING AND PRICING RULES

FLEXIBLE SHIP SCHEDULES AND DYNAMIC DISCOUNTS

SHARED VEHICLE SYSTEMS AND METHODS

MODELING CONSUMER ACTIVITY

SYSTEM AND METHOD FOR VISUALLY BUILDING A MARKET SIMULATION

Systems and methods for providing up-to-date information for transactions

CLOUD COMPUTING SOLUTION GENERATION SYSTEMS AND METHODS

NETWORK-BASED MARKETPLACE SERVICE FOR FACILITATING PURCHASES OF BUNDLED SERVICES AND PRODUCTS

CONTENT CREATION AND DISTRIBUTION SYSTEM THAT DYNAMICALLY PRICES ACCESS BASED ON USER BEHAVIOR

PRODUCT SCORE METHOD AND SYSTEM

Development of dynamic business data based on moving spatiotemporal phenomena and events

FACILITATING REVENUE GENERATION FROM DATA SHIFTING BY DATA CENTERS

Automated system for adapting market data and evaluating the market value of items

SYSTEM AND METHOD FOR ANNOTATING WEBPAGES

MULTIPLICATIVE INCENTIVE MECHANISMS

MANUFACTURING COST ESTIMATOR

System, method, and apparatus for settlement for participation in an electric power grid

GLOBAL POSITIONING SYSTEM BASED TOLL ROAD PRICING

SYSTEM, COMPUTER-IMPLEMENTED METHOD, AND NON-TRANSITORY, COMPUTER-READABLE MEDIUM TO DETERMINE RELATIVE MARKET VALUE OF A SALE GROUP OF LIVESTOCK BASED ON GENETIC MERIT AND OTHER NON-GENETIC FACTORS

SYSTEMS AND METHODS FOR TRACKING VALUE

Systems, methods, and computer program products providing a yield management tool that enhances visibility of recovery rates of recovered and disposed assets

Managing supplemental content related to a digital good

HOLDING ACCESS PRICE CONSTANT FOR SELECTED TIME WHEN ACCESS PRICES CHANGE DYNAMICALLY IN AN AUTOMATES SYSTEM FOR DELIVERING REASONABLY PRICED ACCESS TO CONTENT

Systems, methods and apparatus for improved operation of electricity markets

SYSTEMS, APPARATUSES AND METHODS FOR PERFORMING ENTERPRISE ANALYSIS AND SITE ANALYSIS OF INFORMATION TECHNOLOGY COSTS

Competitive Pricing Template

System and method for reclaiming residual value of personal electronic devices

System and method for calculating and displaying price distributions based on analysis of transactions

COMPUTERIZED SYSTEM FOR DELIVERING REASONABLY PRICED ACCESS TO CONTENT TO REMOTELY LOCATED USERS AT PRICES VARYING IN TIME PER USER BEHAVIOR AND WITH AUTOMATED ACCESS TO OUTSIDE WEBSITES MATCHING A USER'S INQUIRY OR INTEREST

AUTOMATES SYSTEM FOR DELIVERING PRICED ACCESS TO CONTENT WHERE PRICES VARY WITH USER BEHAVIOR, INCLUDING FACILITIES TO DERIVE ACCUMULATED RATING OF ARTICLES, AUTHORS, AND/OR PUBLISHERS AS AIDS FOR LOCATING CONTENT MATCHING USERS' INTERESTS

Demand response event assessment

System and method for aggregation, analysis, presentation and monetization of pricing data for vehicles and other commodities

INTERACTIVE USER INTERFACE FOR RECEIVING AND DISPLAYING MARKET INFORMATION

CONTENT CREATION AND DISTRIBUTION SYSTEM WITH AUTOMATED ESTIMATING, PRIOR TO PUBLICATION, OF VALUES AND/OR READERSHIPS OF ANSWERS TO REMOTELY POSTED QUESTIONS AND MAKING RESULTS AVAILABLE TO REMOTELY LOCATED POTENTIAL PUBLISHERS OF ANSWERS

DYNAMIC PROPERTY PRICING SYSTEM FOR THE REAL ESTATE FIELD AND A METHOD OF PERFORMING THE SAME

DYNAMIC PROPERTY PRICING SYSTEM, SOFTWARE WITH DYNAMIC PRICING AND METHOD OF PERFORMING SAME

PRODUCT RE-PRICING SYSTEMS AND RELATED METHODS

SPEND ANALYSIS SYSTEM AND METHOD

FUEL PRICE DATA GENERATION

Flexible energy use offers

SYSTEM AND METHOD FOR GENERATING PRICING INFORMATION

Method and server for providing a set of price estimates, such as air fare price estimates

DYNAMIC PRICE ELASTICITY IN UNSTRUCTURED MARKETPLACE DATA

RETAIL OPTIMIZATION FOR MARKDOWN

Online Optimization and Fair Costing for Dynamic Data Sharing in a Cloud Data Market

System, method, and apparatus for settlement for participation in an electric power grid

ROBUST PRICING SOLUTION FOR PRODUCTS AND SERVICES

PROJECTED MAINTENANCE REVENUE FOR FUTURE TIME PERIODS

System, method, and apparatus for settlement for participation in an electric power grid

ATTACHABLE CONTINGENT SERVICE PRICING

Methods and systems to price customized virtual machines

RECOMMENDING AND PRICING DATASETS

JUST-IN-TIME GUARANTEED ADVERTISEMENT SUPPLY FORECASTING SYSTEM AND METHOD

RECOMMENDING AND PRICING DATASETS

System, method and computer program for varying affiliate position displayed by intermediary

METHOD AND SYSTEM FOR IDENTIFYING ITEMS AND MANAGING A COLLECTION OF ITEMS

INTERCONNECTED PLATFORMS FOR PROVIDING ADVERTISEMENTS

MARKDOWN OPTIMIZATION SYSTEM HAVING BENEFITS ANALYSIS AND REPORTING

Method and system for determining the vertical alignment of an infrastructure corridor

Development of dynamic business data for marketing to moving spatiotemporal phenomena and events

INFORMATION GATHERING AND PRICE FORECASTING FOR HEAVY EQUIPMENT SALES

OBTAINING OPTIMAL PRICING STRATEGY IN A SERVICE ENGAGEMENT

Optimizing allocation of configuration elements

SYSTEM AND METHOD FOR MONITORING AND PROMOTION OF BEHAVIORS WHICH IMPACT HEALTH CARE COSTS

PERSONALIZED PRICING FOR OMNI-CHANNEL RETAILERS WITH APPLICATIONS TO MITIGATE SHOWROOMING

SYSTEMS AND METHODS FOR PROVIDING FINANCIAL CONTROLS FOR AGGREGATED WEATHER-BASED WORK

SYSTEM AND METHODS FOR AGGREGATING INVESTMENT, EDUCATIONAL AND ENTERTAINMENT DATA AND DISPLAY OF THE DATA THEREOF

SYSTEM AND METHOD FOR FACILITATING DEALER TRANSACTIONS

SYSTEMS, METHODS, AND COMPUTER PROGRAM PRODUCTS FOR MANAGING FUEL COSTS

Demand and supply adjustment system

SYSTEM AND METHOD TO CONTROL DISTRIBUTION OF GOODS IN A VIRTUAL MARKETPLACE

Generation of cost-per-braking event values

PRODUCT PROMOTION OPTIMIZATION SYSTEM

COMPETITOR PREDICTION TOOL

DYNAMIC PRICING FOR FINANCIAL PRODUCTS

Network-implemented methods and systems for providing dynamic product pricing

CROWDSOURCED INITIATIVES TRACKING, DEVELOPMENT, EVALUATION AND SCORING

Prognostics-Based Estimator

Terrace-Based Computer System for Sale and Purchase of Items and Products

SYSTEMS AND METHODS FOR AUTOMATIC PRICE MATCHING

System, method, and apparatus for settlement for participation in an electric power grid

Warehouse Control System With Dynamic Process Control

System, method, and apparatus for settlement for participation in an electric power grid

Enterprise architecture system and method

METHOD AND SYSTEM FOR OPTIMIZING PRODUCT INVENTORY COST AND SALES REVENUE THROUGH TUNING OF REPLENISHMENT FACTORS

METHOD AND APPARATUS FOR PRICING NEW PRODUCT, SERVICE OR SOLUTION

FORECASTING AND MANAGEMENT SYSTEM AND METHOD CONCERNING TICKET TRANSACTIONS IN MULTIPLE MARKETS

SIMULTANEOUS RETAIL AND TRANSFER PRICE OPTIMIZATIONS

COMPUTER METHOD AND APPARATUS FOR OUTCOME-BASED PRICING OF GOODS AND SERVICES

SYSTEM AND METHOD FOR FORECASTING PRICES OF FREQUENTLY- PROMOTED RETAIL PRODUCTS

Data object store and server for a cloud storage environment, including data deduplication and data management across multiple cloud storage sites

SUBSCRIPTION-BASED MOBILE READING PLATFORM

SUBSCRIPTION-BASED MOBILE READING PLATFORM

Method and System for Automatic Generation of an Offer to Purchase a Valuable Object and Automated Transaction Completion

Method for Operating a Restaurant and its Food/Beverage Pricing

Market Price based Raw Material Procurement

RETROACTIVE DOCUMENT RETENTION, REPORTING AND PRICING DETERMINATION

PRICE PAID DATABASE METHOD AND SYSTEM

Managing time-substitutable electricity usage using dynamic controls

Managing time-substitutable electricity usage using dynamic controls

System and method for sales generation in conjunction with a vehicle data system

System Containing An Integration Of Cost Savings Tracker And Spend Analyzer For Calculating Actual Effective Savings

METHOD AND SYSTEM FOR VEHICLE LEASES PERMITTING MULTIPLE VEHICLE EXCHANGES

CROWD PRICING SYSTEM AND METHOD HAVING TIER-BASED RATINGS

ESTIMATING THE TOTAL SALES OVER STREAMING BIDS

ANCILLARY SERVICE BID GENERATION SYSTEMS AND METHODS

System, method, and apparatus for settlement for participation in an electric power grid

Methodology and Process to Price Benchmark Bundled Telecommunications Products and Services

COMPETITOR RESPONSE MODEL BASED PRICING TOOL

REACTIVE COMPETITOR PRICE DETERMINATION USING A COMPETITOR RESPONSE MODEL

COMPETITOR PRICING STRATEGY DETERMINATION

CONSTRUCTION PROJECT SUBMITTAL MANAGEMENT

Product evaluation system and product evaluation method

METHODS AND SYSTEMS FOR AUTOMATIC, PRE-SALE PRICE MATCHING

Intermediate apparatus

METHOD AND SYSTEM FOR DETERMINING AN OPTIMAL LOW FARE FOR A TRIP

PRICE ASSURANCE ENGINE

SYSTEM AND METHOD FOR PRE- AND POST-INVOICE COMPONENT LEVEL PRICE AUDITING IN A COST-PLUS DISTRIBUTION ENVIRONMENT

Cloud network social engineering system and method for emerging societies using a low cost slate device

SIMULTANEOUS RETAIL AND TRANSFER PRICE OPTIMIZATIONS

System and method for modeling and forecasting cyclical demand systems with dynamic controls and dynamic incentives

HOUSING PRICE ESTIMATOR

Computerized method and system for dynamically creating and updating a user interface

STORE PROVIDING SYSTEM, PRICE DECIDING DEVICE, AND PRICE DECIDING METHOD

Method, system and computer program product for dynamically pricing perishable goods

PERFORMING PREDICTIVE PRICING BASED ON HISTORICAL DATA

SYSTEM , METHOD AND COMPUTER PROGRAM FORECASTING ENERGY PRICE

GENERATING A DISCOUNT FOR LACK OF MARKETABILITY

SYSTEM AND METHOD FOR DETERMINING THE MARKET PRICE FOR AN INDIVIDUAL DIAMOND

MONITORING TRANSPORT OF MATERIALS IN CONTAINERS

SYSTEM, COMPUTER-IMPLEMENTED METHOD, AND NON-TRANSITORY, COMPUTER-READABLE MEDIUM TO DETERMINE RELATIVE MARKET VALUE OF A SALE GROUP OF LIVESTOCK BASED ON GENETIC MERIT AND OTHER NON-GENETIC FACTORS

Price estimation model

Implementing comparison of cloud service provider package offerings

CLOUD SERVICE OPTIMIZATION FOR COST, PERFORMANCE AND CONFIGURATION

SYSTEMS AND METHODS FOR PROVIDING VEHICLE MARKET ANALYSIS

Pricing system for identifying prices for vehicles offered by vehicle dealerships and other entities

Dynamic re-pricing of items on electronic marketplaces and/or online stores

System and Method for Estimating Price Sensitivity and/or Price Aggregation for a Population Having a Collection of Items

Method and systems for distributed signals for use with advertising

Methods and systems for a virtual marketplace or exchange for distributed signals

Methods and systems for a virtual marketplace or exchange for distributed signals including data correlation engines

Methods and systems for signals management

Methods and systems for signal construction for distribution and monetization by signal sellers

Price estimation model

DYNAMIC PRICING OF HEALTHCARE RESOURCES

Price scoring for vehicles using pricing model adjusted for geographic region

Automated system for adapting market data and evaluating the market value of items

Integrated online store

System and method for calculating and displaying price distributions based on analysis of transactions

System and method for aggregation, analysis, presentation and monetization of pricing data for vehicles and other commodities

SYSTEM AND METHOD FOR THE ANALYSIS OF PRICING DATA INCLUDING PRICING FLEXIBILITY FOR VEHICLES AND OTHER COMMODITIES

METHODS AND SYSTEMS FOR SETTING OPTIMAL HOTEL PROPERTY PRICES

APPARATUS, SYSTEM AND METHOD FOR RETAL-TIME PRICING ON CONSUMABLE ITEMS IN REATIL EMBODIMENTS

CONTENT PROVISIONING AND REVENUE DISBURSEMENT

SYSTEMS AND METHODS FOR WATERFALL ADJUSTMENT ANALYSIS

SYSTEMS AND METHODS FOR PRICE POINT ANALYSIS

SLIDER BASED PRICING USING MULTIPLE DATA POINTS

Interface for Price Determination

Method and Apparatus to Calculate Social Pricing Index to Determine Product Pricing in Real-Time

METHOD AND SYSTEM FOR DETERMINING THE VERTICAL ALIGNMENT OF AN INFRASTRUCTURE CORRIDOR

METHOD AND SYSTEM FOR PROVIDING A QUOTE FOR PRODUCTS FROM A CUSTOMER RELATIONSHIP MANAGEMENT SYSTEM

Dynamic determination of localization source for web site content

Computerized method and system for dynamically creating and updating a user interface

System and method for transaction based pricing

SUBSCRIPTION PRICING SYSTEM, METHOD AND COMPUTER PROGRAM PRODUCT THEREFOR

ESTIMATING FEES AND COSTS INCURRED BY PATIENT BASED ON INDIRECTLY ACQUIRED DATA OR PATIENT ENTERED DATA

INFORMATION INDICATING FEES AND COSTS TO COMPLETE DELIVERY OF A HEALTHCARE SERVICE TO A PATIENT AND AN ALTERNATIVE TO THE HEALTHCARE SERVICE

FORECASTING FEES AND COSTS TO COMPLETE DELIVERY OF A HEALTHCARE SERVICE TO A PATIENT

Estimating fees and costs incurred by a patient receiving a healthcare service

System, method, and apparatus for settlement for participation in an electric power grid

Transactive control and coordination framework and associated toolkit functions

Method and medium for dynamic property re-pricing using partial broker services

Analytical Tool

FUEL OFFERING AND PURCHASE MANAGEMENT SYSTEM

Automated valuation model with customizable neighborhood determination

System and method for providing electronic price feeds for tradeable objects

SYSTEMS AND METHODS FOR SIMULATING A PRODUCT AT DIFFERENT ATTRIBUTES AND LEVELS

System and method for price testing and optimization

DETERMINING A PRICE

Information processing apparatus, method for generating electric power price list, information processing system, and display device

METHOD AND SYSTEM FOR RISK AND CONSTRAINT BASED PRICING MODEL OF A CATALOG SERVICE TO ASSESS ENTERPRISE NETWORK TRANSFORMATION

AUTOMATED PRICES

ESTIMATING MARKET-DRIVEN MEDICAL FACILITY RATES AND/OR CHARGES

Adjustment simulation method for energy consumption

SYSTEMS AND METHODS FOR MODEL SELECTION

ELECTRIC POWER DEMAND RESPONSE SYSTEM AND METHOD

System for optimizing drink blends

System, method, and apparatus for settlement for participation in an electric power grid

System and method for analysis and presentation of used vehicle pricing data

SYSTEMS AND METHODS FOR REAL-TIME PRODUCT PRICING OPTIMIZATION

Distributed forecasting and pricing system

PRICE MINING SYSTEM AND METHOD FOR MINING THE PRICE

SAVINGS-GUARANTEE APPARATUS AND METHOD

COMPREHENSIVE COST MODELING OF SUSTAINABLY AUTOGENOUS SYSTEMS AND PROCESSES FOR THE PRODUCTION OF ENERGY, MATERIAL RESOURCES AND NUTRIENT REGIMES

Sales system and business method including computer apparatus and product for and method of determining price

Online store product availability

METHOD AND SYSTEM TO FORECAST REPAIR COST FOR ASSETS

PERPETUALLY DECREASING GROUP PRICING SYSTEM AND METHOD

Method and system to schedule repairs for vehicles

System And Method For Presenting Big Data Through A Web-Based Browser Enabed User Interface

Data usage monitoring

TRACKING FOR ROYALTY DETERMINATION

Tracking For Royalty Determination

Method for Financing and Operating Onsite Renewable Energy Systems with Aggregated Onsite Demand

Web based repair cost estimating system

AUTOMATED FEATURE-BASED ANALYSIS FOR COST MANAGEMENT OF DIRECT MATERIALS

SYSTEMS AND METHODS FOR DEMAND RESPONSE PAYMENT OPTIONS

System, method and computer program for forecasting residual values of a durable good over time

MODEL-BASED DYNAMIC PRICING FOR MANAGED LANES

System and Methods for Brute Force Traversal

ELECTRONIC SYSTEM FOR VALUATION AND AN ELECTRONIC PROCESS FOR SAME

COMPETITIVE ECONOMY AS A RANKING DEVICE OVER NETWORKS

Systems and methods for analysis of legal service providers and comparative unit costs or ratio costs

System and Methods for Generating Price Sensitivity

Framework for marketplace analysis

METHOD FOR DRIVERS OF MOTOR VEHICLES OR MOTOR BOATS TO LOCK IN THE PRICE THEY PAY FOR FUEL IRRESPECTIVE OF THE QUANTITY OF FUEL THEY USE IN THE FUTURE

REVENUE OPTIMIZATION PLATFORM APPARATUSES, METHODS, SYSTEMS AND SERVICES

Computer Implemented Methods For Providing Customized Marketing Information

TREE-BASED REGRESSION

System and Methods for Revenue and Impact Analysis of Price Protection and Price Caps

METHOD AND SYSTEM FOR INVENTORY FINANCING AND MANAGEMENT

SYSTEM AND METHOD FOR ORGANIZING PRICE MODELING DATA USING HIERARCHICALLY ORGANIZED PORTFOLIOS

MANIPULATION OF MULTI-DIMENSIONAL PRICING STRUCTURES

SYSTEM AND METHOD FOR MANAGING CONTENTS PRICE

DISPENSATION SYSTEM

Commerce System and Method of Price Optimization using Cross Channel Marketing in Hierarchical Modeling Levels

SYSTEM AND METHOD FOR OPTIMIZING REVENUE AND PROFIT WITH LIMITED NUMBER OF PRICE CHANGES

METHOD AND SYSTEM TO MANAGE TRAVEL COSTS

SYSTEM AND METHOD FOR GENERATING PRICING INFORMATION

RECALL AND MARKET WITHDRAWAL ANALYSIS

Method and medium for dynamic property re-pricing using partial broker services

Method and apparatus for creating a personalized question feed platform

System and method for sales generation in conjunction with a vehicle data system

AERIAL ROOF ESTIMATION SYSTEM AND METHOD

Generating an Optimized Pricing Plan

Systems and methods for an online marketplace for accessories of a remote monitoring and management product

SYSTEMS AND METHODS FOR AN ONLINE PAYMENT SYSTEM WITH CREDIT NOTES

Fuel price activation and management system

Method and system for determining the vertical alignment of an infrastructure corridor

SYSTEMS AND METHODS FOR EVALUATING PROPERTY VALUATIONS

SYSTEMS AND METHODS FOR ESTIMATING COST OF SYSTEM TESTING REQUEST BASED ON TABLE UNIT

DATA PROCESSING SYSTEM FOR PRICING, COSTING AND BILLING OF FINANCIAL TRANSACTIONS

Method and System for Analyzing a Plurality of Parts

Method and System for Differential Pricing in the Distribution of Digital Content

METHOD AND SYSTEM FOR DIGITAL CONTENT PRICING

Systems and methods for tailoring marketing

Systems and methods for tailoring marketing

Systems and methods for tailoring marketing

Systems and methods for tailoring marketing

Systems and methods for tailoring marketing

Data gathering in digital and rendered document environments

METHOD, APPARATUS, AND COMPUTER PROGRAM PRODUCT FOR A PRICING UTILITY

SYSTEM AND METHOD FOR CUSTOMER VALUE CREATION

Performing data storage operations with a cloud environment, including containerized deduplication, data pruning, and data transfer

Automated valuation model using ordinal variables such as condition and quality variables

SYSTEM AND METHOD FOR DYNAMIC PRODUCT PRICING

Data Processing Based on Online Transaction Platform

SYSTEM, METHOD AND COMPUTER PROGRAM PRODUCT FOR ATTRIBUTING A VALUE ASSOCIATED WITH A SERIES OF USER INTERACTIONS TO INDIVIDUAL INTERACTIONS IN THE SERIES

System and Methods for Time Dependent Internet Pricing

System and method for network access vending

Real Estate Search Engine

SYSTEM FOR DETERMINING A TRADE-IN VALUE OF AN ITEM BASED ON A MATCH TO A DATABASE OF CUSTOMERS

Method and system for analyzing and optimizing distribution of work from a plurality of queues

Product Pricing in E-Commerce

RETAIL PRODUCT PRICING MARKDOWN SYSTEM

Method and system to connect consumers to information

PROPERTY APPRAISAL EVALUATION USING TRAFFIC DATA

SYSTEMS AND METHODS FOR IMPROVED CALCULATION OF COEFFICIENT FOR PRICE SENSITIVITY

FIXED PRICING OF SERVICES

Method and system for collecting and parsing market data from various sources

DYNAMIC MULTI-DIMENSIONAL AND MULTI-VIEW PRICING SYSTEM

Utility for determining competitive restaurants

Energy-disutility modeling for agile demand response

SYSTEM AND METHOD FOR COMPUTING A VARIABLE FUEL PRICE BASED ON EXHAUST GAS EMISSIONS OF A VEHICLE

Comment submission support system, comment submission support device, comment submission support device control method, program, and information storage medium

System and method for managing and evaluating network commodities purchasing

SPORTS AND CONCERT EVENT TICKET PRICING AND VISUALIZATION SYSTEM

PRICE SIMULATION FOR ENTERPRISE SALES AND SUPPLY PROCESSES

PRICE DETERMINATION SYSTEM, PRICE DETERMINATION SYSTEM CONTROL METHOD, PROGRAM, AND INFORMATION STORAGE MEDIUM

METHOD AND SYSTEM FOR PROVIDING A HOME DATA INDEX MODEL

Automated valuation model with customizable neighborhood determination

DEFINING A MARKDOWN EVENT USING STORE CLUSTERING METHODOLOGY

SYSTEM AND METHOD FOR TIERED OFFER FORECASTING

Systems and methods for controlling energy use in a building management system using energy budgets

SYSTEM AND METHOD FOR HEALTH CARE FINANCING

SYSTEM FOR PRICING INDIVIDUALLY QUOTED WHOLESALE FUEL PURCHASES

SYSTEMS AND METHODS FOR INSURANCE PRODUCT PRICING AND SAFETY PROGRAM MANAGEMENT

Method of analyzing a sale process for an entity

Aggregator-based electric microgrid for residential applications incorporating renewable energy sources

System and Method for Developing Sales Content

Real time service advertisement for billing and revenue settlement in a federated model

Computer method and apparatus for outcome-based pricing of goods and services

System and method for analysis and presentation of used vehicle pricing data

Method and system for determining an optimal low fare for a trip

Data object store and server for a cloud storage environment, including data deduplication and data management across multiple cloud storage sites

Aggregator, monitor, and manager of distributed demand response

System and method for the analysis of pricing data including a sustainable price range for vehicles and other commodities

System, method and computer program product for geo-specific vehicle pricing

METHOD AND SYSTEM FOR REVENUE MANAGEMENT SYSTEM BASED ON MARKET PRICING

Managing and evaluating price data for purchasing