1. A mobile payment system for effecting payment for a financial transaction in a payment processing system, the mobile payment system comprising: a financial transaction token including: an onboard energy source; memory coupled to the onboard energy source and configured to store and retrieve data regarding an account in the payment processing system; an embedded processor coupled to the onboard energy source and the memory; and an electrical interface in communication with the embedded processor; and a mobile subscriber unit including: an integrated processor in communication with the electrical interface; storage, coupled to the integrated processor and configured to store and retrieve code executable by the integrated processor; and a transceiver coupled to the integrated processor and an antenna; wherein upon the integrated processor, sensing a predetermined condition indicating the initiation of the financial transaction, executes at least some of the code stored in the storage to: obtain, through the electrical interface, the data regarding the account; and transmit the data regarding the account through the transceiver.