An ink billing system is used between a client company X 200 that prints information and a printer manufacturer that supplies ink cartridges (or toner) to the company X 200. The company X 200 has a main server 210, a plurality of in-store servers 220, 230 in communication with the main server, and a plurality of inkjet (or laser) printers 240 each having an ink cartridge 20 (or toner) for printing according to commands from the in-store server 220, 230. When billing the company X 200 based on the number of ink shots (or drum charging time) used by the printers 240 and stored on the main server 210, the terminal device 100 of the printer manufacturer changes the billing rate per unit of ink according to the ink shot count (or drum charging time).