Make sure you are signed in on the website first, as a guest coupons and other rewards will not all work.
(1) You can also enter Coupon Codes in the shopping cart page and can also be entered in checkout page. Enter the code lower or uppercase doesn't matter. Make sure no spaces before or after the code in the box and then hit apply.
(2) You can enter Store Credit at the end of checkout near place order button. Click on store credit and then enter the amount you would like to use hit apply. To see your store credit balance look in your account.
(3) To use Rewards Points at the end of checkout near place order button there is a rewards points option. Click on it and then add the points you would like to use. 100 point equals $1. To see your rewards points balance look in your account.
In the discounts breakdown under subtotal will show all the discounts. Click on it or tap to expand and show each discount.