Thanks to some tricky in-app purchases, some kids are running up HUGE bills while playing supposedly free iPhone and iPad games. Games like Angry Birds and Zombie Takeover are free to download, BUT pop-up messages during gameplay offer upgrades for a fee. Any purchases are automatically charged to the account holder's credit card. One mom learned this the hard way after her six-year-old son charged more than a thousand bucks playing a game on her iPad! If your game app requires a password to make purchases, now is the time to set it up to keep your budget intact!