Discount promo codes are entered in the Gift card or discount code box during checkout. If you receive an error message, it may mean that your code has expired or you have not met the minimum purchase amount required. Check your code for any typos and try again.
One discount code per order, discount codes can't be stacked with 'Build a Set' discounts. If you build a set and use a code, you'll automagically get the best deal of the two at checkout.