Methods and systems for self-service checkout. In an embodiment, a mobile device processor of a consumer's mobile device receives input data of an item selected for a purchase transaction, displays information concerning the item on a display screen, and receives an indication from a consumer that shopping is completed. The method includes transmitting checkout data for the purchase transaction to a self-service checkout computer, receiving a transaction authorization message and merchant instructions from the self-service checkout computer, and then displaying on the display screen the transaction authorization message and the merchant instructions, wherein the merchant instructions direct the consumer to exit the particular merchant store in a particular manner.