1. A mobile user device enabled for wireless payment, comprising: a cellular wireless interface; a global positioning system (GPS)-based wireless receiver; and a short range radio frequency device disposed on or in the mobile user device; wherein the mobile user device is configured to be encoded with payment source information specific to a user of the device, the payment source information allowing the user to use the mobile user device to wirelessly pay for at least one of goods or services by placing the mobile user device in proximity to an interrogation or reader apparatus at a point of sale of said goods or services; wherein the short range radio frequency device and payment source information obviates the user from having to carry at least one other currency or payment source on their person; wherein the radio frequency device comprises a passive radio frequency identification device configured to utilize radio frequency energy incident thereon and generated from the interrogation apparatus or reader to generate a reply, the reply including at least a portion of the payment source information; and wherein the short range radio frequency device is disposed on or in the mobile user device at time of manufacture of the mobile user device, the radio frequency device comprising an integrated circuit with data memory, and an antenna.