To provide a system allowing a supplier of commodities to know true needs of a prospective consumer to allow the prospective consumer to purchase the commodity agreeable to oneself which the prospective consumer truly wishes, in a commodity transaction method using the Internet.

In this transaction method for the commodity, the supplier of the commodities opens a commodity sales web page on a server 1 connected to the Internet 2, and the prospective consumer accesses the web page to execute a process related to commodity purchase. A function 6 related to the commodity and an input space 8 for inputting desired conditions about the function 6 are displayed on a screen 3a of the home page, prospective consumer's data inputted in the input space 8 is transmitted to the supplier, the commodity is manufactured on the basis of the sent data, and a finished product is delivered to the prospective consumer.