Abstract: Methods, systems, and apparatus, including computer programs encoded on computer storage media, for tracking a product item in an automated-checkout store. One of the methods includes receiving, from a plurality of sensors, data collected by the sensors, identifying an account associated with a person who enters the store, receiving data on movement of the product item collected by one or more of the sensors, determining an interaction between the person and the product item based on the data collected by one or more of the sensors, storing information associating the product item with the person; and deducting a payment amount from the identified account, wherein the payment amount is based on a price of the product item associated with the person.