Abstract: A purchaser of a gift certificate registers a paying method, a using condition, a password, and a delivery target in a server, using a terminal. The server (issuer) issues the gift certificate that has no face value, a gift certificate number as a specific code, and the using condition, and sends the gift certificate to a registered user. The user who received the gift certificate, in buying a commodity in a store, logs in to the server from a terminal for the store, and inputs the gift certificate number and information of the bought commodity. The server requests input of a password, and, when the correct password is input, makes payment of the commodity by the registered paying method.