Devices, methods, and programs for billing for electric power. A billing method may include generating billing information for an amount related to electric power transmitted by a power supply device, performing a billing process based on the billing information, and selectively transmitting electric power based on the result of the billing process. A power supply device may include a billing information generating unit, a billing processing unit, and a power control unit. Another billing method may include determining whether billing information has been received, performing a billing process after it is determined that the billing information has been received, transmitting a response signal to a power supply device, and providing notice regarding information related to the billing process. A power receiving device may include a billing processing unit, a power control unit, and a notice control unit.