First of all I created tournament for 20 fee. When I joined it asked for 20 gold, it's ok. But then I realised that no one going to play it I leaved tournament. And lost 20 gold for nothing, because it wasn't returned.

Then I created tournament with 10 fee, paid 10 after entered it, then won it, but got no gold at all (instead 20). I tried to repeat bug and created one more tournament with 2 fee, played with grug, won and got no gold again (except 1 gold per battle of course).