A portable wireless communication terminal installed on a shopping cart includes a reader, a wireless communication interface, a display, and a processor. The processor is configured to control the reader to read a commodity code that identifies a commodity to be purchased by a customer in a store, determine whether or not the commodity code read by the reader is associated with the store, determine a retrieval code based on a result of the determination about the commodity code, wirelessly retrieve from a database through the wireless communication interface, one or more pieces of information for promotion using the determined retrieval code, and control the display to display one of the retrieved pieces of information about a commodity available for sale in the store.