Don't confuse Barcodes with UPC codes.
Barcodes are for use in your store to track your inventory and post them to an invoice and properly post in your accounting software for COGS. The barcode and scanners outside your office will not work. Your barcode will tell you retail, cost, item, supplier and numerous other details. Consider it an IN HOUSE system ONLY.
UPC code is for your items if you want to sell them in retail stores or on Amazon. UPC codes will work on any system and it can tell you the manufacturer, retail price. the UPC code is universal and is purchased and is unique to only your product anyplace it is sold.
Unless you plan to sell 100's of items in numerous retail store, don't waste the money. For a few items you want to post on Amazon, then just buy a few at a couple $ each.
Business owner using UPC and Barcode.