Abstract: A method of handling negotiations between a seller of an item and prospective buyers of the item is disclosed. A first offer for the item is received. The first offer includes a first item price and a first item quantity. A second offer for the item is received. The second offer includes a second item price and a second item quantity. It is detected that a first prospective buyer submitted a payment corresponding to the first offer before a second prospective buyer submitted a payment corresponding to the second offer. Based on an item quantity of the seller being less than the first quantity plus the second quantity, the seller is notified that the seller has an obligation to provide the first item quantity of the item to the first prospective buyer, but not the second quantity of the item to the second prospective buyer.