If you receive a promo code from your school or see a code advertised during a campaign, you can use that code when you reach the shopping cart in USMLE-Rx. Here are the steps to take.
First, go to the product page and select the product that you want to purchase.
Then, when you reach the shopping cart, click on the link that says "I have a coupon."
When you open it, add the promo code in the coupon code field and then click Apply Coupon. From here, click Checkout.