A prepaid mobile phone also known as pay-as-you-go or prepaid wireless is a mobile phone for which service is purchased in advance of use, this is the typicall alternative billing method is what is commonly referred to as a mobile phone contract. With the prepay option you can purchase credit to use on a mobile phone network, where you can access a mobile phone network without ongoing billing. Users can then use the mobile phone network until they run out of credit. , where a user enters into a long-term billing arrangement with a mobile network operator or carriage service provider.