A personal bar code scanning device for aiding shoppers in keeping track of their expenditures and speeding the process of check-out and taking advantage of coupons. A microprocessor coupled to a bar code reader, a communication port, an audible feedback device and a touchscreen or light pen and display combination carrys out bar code scanning in a store as a shopper shops. The user selects a shopping list from a collection of one or more shopping lists or creates a new list from a database or by spelling out the items to purchase on a keyboard. The user then downloads the store's current price list by modem or by connecting to the store computer when the store is entered. When the shopper wishes to purchase an item, the personal bar code scanning device is placed adjacent to the bar code on the package of the item and the user presses a button to scan the bar code. The bar code is then imaged by a CCD device, and the pattern of light and dark bars is decoded into an ASCII string which is stored in memory and compared to the current shopping list and the current price list. When a match is found, the display is changed to indicate the item scanned has been put in the basket. The price of the item is then added to the running total. In some embodiments, when the price list is downloaded, there is automatically downloaded a coupon list of items currently on sale. When an item is scanned, the ASCII identification string is compared to the coupon list, and, if a match is found, the discount from the coupon is automatically applied before updating the running total. In some embodiments, a magnetic security strip is used next to the bar code. The personal bar code scanner includes a pair of permanent magnets or electromagnets to generate a D.C. or nonvarying magnetic field which can envelope the magnetic security strip to deactivate it when an item has been scanned. This prevents the item from setting off security alarms when passing a security device at a store exit. In some embodiments, the Personal Scanner.TM. device is mounted on a shopping cart for use by user's who do not own their own devices.