A method for preventing redundant purchases of limited items includes steps for providing a commerce client to a user, receiving (a) financial information of the user and (b) a device identifier from a device the user is using to run the commerce client, the device identifier being based on one or more of user-configurable and non-user-configurable parameters of the user device, determining whether a previous transaction has been made with the device associated with the received device identifier, and disallowing the device from executing further transactions for a predetermined period of time. The method may be executed by an apparatus such as a computer server or stored as a series of instructions on a computer readable medium.