Available here: http://www.waspbarcode.com/SEARCH/Product.asp?Item=191504Then you need to create barcodes for your products in Filemaker. I recommendhttp://sixfriedrice.com/wp/products/6barcode/
A little scripting and experimentation/development and you have a system to track transactions and Inventory. Every Item will need a Serial number that will link it to related info in the database we've set up like photos, prices, quantity in stock, whatever is needed. The scanner translates the bar code into a number to add an item to an invoice, remove it from inventory as needed.
The Filemaker script will look like this:
Its not too complicated. Please contact me with any further questions. email@example.com