There's a part of FIFA called Fifa Ultimate Team (FUT) where you put together your own squad through a trading card system, you can buy packs of players with real money or with 'coins' earned by winning games against the computer online. You can also trade players on an online auction house...
The AI flat outs cheats you when it wants to, you know when its happening...every second ball falls to an opposing player, defenders bunping into each other and spazzing out when your trying to defend, dubious off side decisions. It's infuriating.