A wireless system for self-service shopping is described that includes a customer identification device with an optically readable code, a portable terminal that includes an optical code reader, a local area radio, a terminal controller, and a locking mechanism, a master station, consisting of a master controller and a master radio, and a receiving rack for the portable terminals to which the scanners may be locked using the locking mechanism. A customer presents his or her identification device to a terminal which reads the code, the code is transferred by radio to the master controller which checks the identification and, if valid, sends an authorized signal by radio to the terminal to unlock the scanner. In addition, several locking mechanisms are described that are controlled by the terminal controller. An additional feature provides a shopping cart with a receiving cradle for a portable terminal that allows the customer to lock the scanner onto the cart for hands-free shopping.