Methods and systems are provided for enabling users of mobile devices to purchase Ring Back Tones (“RBTs”). The system enables an offer message, offering for purchase an RBT and including a reply-to telephone number, to be generated and sent to a mobile device. In response to the offer message, a reply message sent from the mobile device to the reply-to telephone number of the offer message is received. A code is extracted from the reply-to telephone number to which the received reply message was sent. A particular RBT associated with the code extracted from the telephone number is identified in a table storing a plurality of codes each associated with a corresponding RBT. A user of the mobile device is determined to desire to purchase the particular RBT associated with the code in the table.