A system and a method for performing purchase transactions over a network are provided. The system includes a server controlled by a service provider, including a link to a network; a processor circuit, the processor circuit configured to receive purchase requests from a mobile phone, and to transfer funds from a user account to a vendor account; and a memory circuit storing a plurality of mobile phone numbers and a plurality of personal identification numbers (PINs), wherein each mobile phone number and PIN is associated with a user account. A non-transitory machine-readable medium may include a plurality of machine-readable instructions which when executed by one or more processors of a server controlled by a service provider are adapted to cause the server to perform a method as above.