That could be possible. I could make it switch a trigger on when you use the item then if you win the battle it doubles your exp or gold and resets the trigger. If you lose it will just reset the trigger. I'm not sure about using it outside of battle though. I would have to add something to the character profile that shows they have an active exp or gold multiplier. And if it's only a battle item it will take up one of the 5 item slots and the whole reason I made the Charm and Mount slots was so people didn't have to sacrifice an item slot for a Chocobos and charms.