Abstract: A method for providing to purchasers of goods, including used goods, availability to an on-line market at which the purchasers' needs can be fulfilled from one or multiple sources in the context of a reverse-auction, includes the steps of one or more buyers posting to an on-line market one or more desired exchange items, one or more sellers posting to the on-line market one or more offers to sell one or more exchange items, a buyer accepting, in whole or part, at least one of the sellers' offers, the buyer entering how much of each of the sellers' offer(s) it accepts, and an on-line marketplace provider notifying via e-mail at least one seller of a buyer's acceptance of the seller's offer.