Kamikaze
Auto-translated
Well, don't say that. You take a spell like Inhibition or Vulnerability and sell 5-6 scrolls for about 3,000 gold each (at the beginning of the game), you make an extra twenty grand, buy some troops, and go into battle.
But there's also a bug, and I think it only works on Hot Seat mode, where you can see the opponent's forces by watching their turn.