1. A method of processing a promotion from a first party, the first party having a first system, the method comprising: offering, by a second system of a second party, an item for sale online at a sales price amount, the item for sale having associated with it, by the second system of the second party, a promotion from the first party, the promotion having a promotion amount, wherein the second system is distinct from the first system and the second party is distinct from the first party; receiving, by the second system, an online purchase request from a buyer for the item for sale; responding, by the second system, to the online purchase request by collecting from the buyer a purchase amount corresponding to the sales price amount less the promotion amount; and causing, by the second system, shipment by the second party of the item for sale to the buyer.