A system including a cellular phone or a telephone card having, pre-registered therein, the identification number of a connection telephone company and a user ID, a store processing terminal unit handling it, a point-of-sale POS terminal, and a management host computer of the telephone company, wherein these are connected through a communication line. A merchandise information of the cellular phone that is transacted, etc., is sent to, and stored in, the host computer. When a call is made using the cellular phone, or the like, the host computer carries out reduction processing of a prepaid telephone charge depending upon a call rate on the basis of the stored merchandise information of the cellular phone, or the like. When the cellular phone or the telephone card is used, telephone charges can be paid in a store handling such a cellular phone, or the like.</PTEXT>