An Amazon promo code is a combination of letters and numbers that can be applied at checkout to receive a discount on an eligible product or order. It is usually for a limited time only and may have specific terms and conditions. A coupon, however, may refer to a physical or digital voucher that can be redeemed in-store or online for savings on a particular item or group of items. Coupons often have expiration dates as well. Both types of discounts can help you save money when shopping on Amazon.