1. A method of providing item availability and pricing transaction information over a network, comprising: registering a first user over a network by an item availability and pricing transaction processing system wherein the registration includes creating a first user account and storing the created first user account in computer readable memory; receiving at the item availability and pricing transaction processing system coupled to at least one data network, a first receipt provided by the first user, for one or more items purchased at a first merchant wherein the first receipt includes associated item prices, or receiving at the item availability and pricing transaction processing system, one or more item prices at the first merchant provided by the first user; storing in a first list by the item availability and pricing transaction processing system, at least one of the received item prices provided by the first user; registering a second user by the item availability and pricing transaction processing system wherein the registration includes creating a second user account and storing the created second user account in computer readable memory; receiving at the item availability and pricing transaction processing system, a second receipt provided by the second user, for one or more items purchased at the first merchant or at a second merchant wherein the second receipt includes associated item prices, or receiving at the item availability and pricing transaction processing system, one or more item prices at the first merchant or at the second merchant provided by the second user; storing in a second list by the item availability and pricing transaction processing system, at least one of the received item prices provided by the second user; providing an item availability and pricing transaction software program on the first user's mobile device; receiving at the item availability and pricing transaction software program, a user request provided by the first user to determine a lowest price of an item or a lowest price of a group of associated items; querying by the item availability and pricing transaction software program, the first user's mobile device GPS capabilities to determine a current geographic location of the first user; determining by the item availability and pricing transaction processing system, one or more merchants located within a configurable distance from the determined first user's current geographic location wherein each of the one or more merchants is a first merchant or a second merchant; querying by the item availability and pricing transaction processing system, the stored first list and the stored second list to determine the lowest price for the item or the group of associated items at the determined merchants located within the configurable distance from the determined first user's current geographic location; and displaying via a first user interface by the item availability and pricing transaction software program, a list of one or more merchants located within the configurable distance from the determined first user's location in which the item or the group of associated items is offered at the lowest price.