Here's how to use Promo Code when shopping in Advantage Trim & Lumber: add new products to the Advantage Trim & Lumber shopping cart and click the checkout. Log in or create a new account to Advantage Trim & Lumber by entering details, then click Continue to pay. Below the listed items, you will see a box that says Add Coupon, choose the Advantage Trim & Lumber Promo Code you are going to use and then the website will automatically return to the checkout page. Now you will see your actual total payment at advantagelumber.com.