Here are the steps on how to use Promo Codes when shopping at rue21.com: Sign in to Rue 21 or create a new account to add your favorite products to your cart. Next, it will jump to the payment page, select Coupon Codes of your Rue 21 on the payment page, and complete the payment. Also, welcome to this promotion from Rue 21 on October: Flash Sale! Get Latest Up To 50% Off Coupon.