Server device, communication system, information-processing device, communication method, and storage medium

A server device includes a storage unit that stores a database that records plural pairs of a user/device ID and a corresponding first parameter, the first parameter indicating an amount of data that the user or the device has a right to communicate via a predetermined network; a first obtaining unit that obtains a user/device ID and a corresponding retail ID from the information-processing device; an adding unit that performs, in a case that the first obtaining unit obtains a user/device ID and a retail ID, an adding process to add a predetermined second parameter to a first parameter corresponding to the user/device ID, from among the plurality of first parameters recorded in the database, the second parameter indicating an amount of data to be added; a second obtaining unit that obtains an amount of data in a communication performed by the information-processing device via the predetermined network.