Here are the steps on how to use Promo Codes when shopping at zeplin.io: Sign in to your zeplin.io account, if you don't already have one, you will need to create a new Zeplin 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 Zeplin Coupons of your choice and automatically return to the checkout page, You will see that the actual payment total has been reduced.