You can purchase the various different types of packs that you use to build your Team in the Store for 7,500 - 200,000 coins or a certain amount of Madden Cash. The Pro Pack is available 24/7 but some of the other packs are only available for a limited amount of time, an example of this is the Super Bowl packs which was only available for a few days. Packs will sometimes include rare collectibles as well as bronze to elite players of varying value.