1. Make sure you correctly type in the UPPERCASE and lowercase letters properly. Most coupon codes at MLB will not work if you don't get it exactly right.
2. Make sure you have the best possible code. I am positive this list is the most up-to-date list of MLB Shop coupons you will find, however if you doubt, why not also check others sites like savings.com
3. If you don't see a deal you like, check back in a few days. New deals are usually posted on Tuesdays.