A payment system having a server apparatus (50) capable of transmitting and receiving information via a communication network (1), a first terminal apparatus (10) for a purchase application, a second terminal apparatus (20) for an installment payment organization and a third terminal apparatus (30) for a settlement service organization. The first terminal apparatus includes an inputting device (104) for prompting to input desirable one of a plurality of payment plan informations each indicating a combination of (i) a part of an installment payment for a purchase price of a product, and (ii) a part of a settlement service for a price of a service, as well as for prompting to input personal information and the credit card number. The server apparatus includes a processing device (502) for extracting (i) information relating to items for an installment payment application and (ii) information relating to items for a settlement service application, separately from among the information inputted via the inputting device.