This is a cool way to get negative coins:
(you have to have a puffle to do this cheat!) First, make sure you have 9 coins or under. Ounce you do, click on your puffle. Try to feed your puffle. It will probably say. You need more coins, right. Well, now check your player card. YOU WILL HAVE NEGATIVE COINS!! BUYING PUFFLE FOOD, ACUALLY TOOK AWAY SOME OF YOUR COINS!! ITS REALLY COOL.