1. A system for modifying a price curve and approaching market equilibrium in an on-line buying co-op for a product, which comprises: (a) an e-commerce server data processing system, said e-commerce server data processing system including e-commerce server software executable on said e-commerce server data processing system and configured to define an on-line buying co-op for a product; (b) a storage device coupled to said e-commerce server data processing system and having stored therein a database including at least price data for the product, quantity data for the product and offer data; and (c) a merchandising staff client data processing system coupled to said storage device, said merchandising staff client data processing system including client software executable on said merchandising staff client data processing system and configured to receive merchandising staff inputs for defining the on-line buying co-op for the product, said client software including a market equilibrium manager to modify a price curve for the product in the on-line buying co-op by utilizing the price data for the product, the quantity data for the product and the offer data in said database.