If you have a dragon that can learn "Be Dragon" use it and then use a "World Dew" on it after it is transformed into the dragon and it will have 999 HP for the rest of the round or until somebody uses "De Magic".
If you want more money instead of arena prizes, fill your pack with cheap crap until you cannot hold any more items. Enter and win an arena match and instead of items, your character is awarded 6000 GP instead.
