An electronic shopping system facilitates purchase transactions via a wireless telephone. A purchase transaction program is downloaded from the seller's server to a purchaser's wireless telephone via a program loader contained within the purchaser's wireless telephone. The purchase transaction program is stored in a program memory of the purchaser's wireless telephone. The purchase transaction program is used by the purchaser to facilitate the selection of items to be purchased, as well as payment therefor. An external bar code reader is attached to the wireless telephone to facilitate the selection of items to be purchased and is controlled via the downloaded purchase transaction program.