Patent ID: 8583505

Claim:
A non-transitory computer-readable medium having embodied thereon a computer program for operating a differential payment system that is connected to a purchaser terminal that purchases services through the communication network, is comprised of: a membership information registration/management module that receives membership registration information from the purchaser terminal; a membership information storage member that stores membership information a credit evaluation/management module that generates a purchase credit of a purchaser using the purchaser's membership information that was inputted through the purchaser terminal; a service evaluation/management module that calculates the service evaluation score using the service evaluation information inputted from the purchaser terminal, after the service is provided to the purchaser; and an installment payment price calculation module that provides the service payment that is to be paid to the service supplier providing the service differentially, in proportion to the service evaluation score and the purchaser's purchase credit, wherein the credit evaluation/management module changes the purchaser's purchase credit score in inverse proportion to the service evaluation score that was based on the evaluation information that the purchaser inputted.