Abstract: A commodity sales system includes at least one server computer including a memory system, a commodity price specification module for receiving a purchase request of a selected commodity from the user computer and for specifying a commodity price of the selected commodity. A storage module that stores a component price table and a maximum/minimum price determination module are also included. A deduction setting module and a tentative quote setting module for setting the minimum price determined by the maximum/minimum price determination module to a tentative quote of the used personal computer are also included.

Abstract: A server system 10 receives a purchase request of a selected commodity from a user computer 40 and specifies a commodity price of the selected commodity. The server system 10 also receives a trade-in request of a used article and quotation requirement information, which is required for quotation of the used article, from the user computer 40 and determines a trade-in quote of the used article, based on the received quotation requirement information. The server system 10 sets a deduction of the selected commodity, which is to be subtracted from the specified commodity price of the selected commodity, according to the trade-in quote of the used article thus determined, subtracts the setting of the deduction from the specified commodity price of the selected commodity to calculate a difference, and sends the calculated difference as an amount payable to the user computer 40.

Abstract: A Web server receives a maximum cash-out quote PAmax of a used article from a database server and calculates a minimum cash-out quote PAmin, a maximum trade-in quote PBmax, and a minimum trade-in quote PBmin of the used article from the maximum cash-out quote PAmax (step S210). The maximum cash-out quote PAmax is compared with a preset threshold value P1 (step S220). When the maximum cash-out quote PAmax exceeds the preset threshold value P1, it is determined that the used article is worth of both a cash-out without purchase of any new product and a trade-in with purchase of anew product. The Web server accordingly creates a quotation window including the maximum cash-out quote PAmax, the minimum cash-out quote PAmin, the maximum trade-in quote PBmax, and the minimum trade-in quote PBmin of the used article (step S230) and sends the quotation window thus created to a user computer.