If you can win the 13 weekly solo battle games on All Madden you get some decent rewards each Monday. Be careful though you will need to play smart football against the higher rated team because on all madden the CPU sometimes becomes unstoppable. When I play a 90 over team I hog the ball and run the clock. With 3 minute quarters a good run game or short passing game can eat up am entire half. I've played a few game where the CPU never got the ball back after the first kick off.
With the solo challenges you can see the rewards by selecting the Milestone tab at the top. Some give you coins and some give you cards. Right now the NFL 100 challenges give you your choice of a 94 over player is you get all 33 stars. These are very easy. you also get a 84-85 over player for each set of challenges. These can be added to a set for a higher rated player or cashed in for training points.