Coupon Barcodes - Barcode Test GS1 Databar Coupon Code not only manages the offer, it tracks the conditions automatically. The offer can mix different brands: buy Product A and get 50% off on Product B. Offers can be very complicated: buy 1 and get 2; buy 1 and get 2 more at half price, etc. Databar Coupons can also define a start date and an end date.