Thanks to /u/crk38 I learned that you can play with any card in the game for free, including Icons and special cards.
You can also find anyone's custom tactics if that interests you.
You need 2 controllers and you need to add someone as a friend who has the player/team you want to test out. It can literally be anyone. Go play a game against a friends squad (then select the guy you just added as a friend that has the player you want to test) and use the second controller to control the 'away team' (the guy's team). You can now play with the person's team. You can even put your first controller in the middle so your own team is ai controlled. You can see his custom tactics and you can use any player he has, gullit, vieira, Ronaldo Nazario, any player that he owns.
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