Abstract: An entity (hereafter “aggregator”) acts as a repository to which sellers submit descriptive information about a product or service available for sale, and business rules (collectively called “product package”) to be used in selling the product or service to buyers. Sellers submit their product packages in a predetermined format (e.g., as a XML file) where individual information within each package are identified by descriptors (e.g., XML tags). The aggregator compiles the product packages from one or more sellers into a catalog that is distributed to buyers as an online catalog, an electronic catalog on a multimedia disk, or a paper catalog. The aggregator customizes the content of the catalog for different buyers and areas of distribution according to the business rules for the products. The catalog can include legally binding offers with words of commitment to sell and specific terms generated from the business rules.