Promo Codes is used as follows: Sign in to your assemblylabel.com account, if you don't already have one, you will need to create a new Assembly Label account. Then, add the selected items to the shopping cart. Next, click on [Proceed to Payment], below the items listed, you will see a box that says [Add Coupon Codes]; tick the Assembly Label Coupons of your choice and automatically return to the checkout page, You will see that the actual payment total has been reduced.