If you're on a budget, you can check out websites like ebay and amazon who too have cheap authentic jerseys. Usually on those sites, people post their items because they were gifts or have overstock!
You can find any teams jersey on MLB. com in their team jersey section. You can find really great deals on used or new jerseys on ebay and amazon. There are also shops in the mall where you are sure to find a Manny Ramirez jersey.