Abstract: Systems and methods of enabling cross-promotion of products and services during a purchase transaction are provided. An offer management system provides contribution offers to a purchaser in response to a request for discounts for a product. Upon acceptance of the offers by the purchaser, the offer management system causes funds to be transferred from one or more contributor payment accounts to a retail point-of-sale system. These funds are combined with funds from the purchaser to provide the full price to the retailer for the product. The offer management system monitors purchaser activity to determine if the purchaser later complies with conditions of the offers. In some embodiments, the offer management system may be used by traditional point-of-sale systems without requiring special configuration to work with the offer management system.