7 Ways to Short-Circuit Kids' Mobile Addiction Part 2

Kids can unwittingly rack up huge bills for hay, jewels or doughnuts in "freemium" games if they're allowed to, and though many app makers will work with parents to refund that money, companies usually make those calls on a case-by-case basis, Markey said.

"This is why passwords are wonderful," Markey said.

Passwords should be in place whenever a credit card purchase is a possibility, Markey said. It's also important not to share passwords with kids, and not to pick ones they can easily guess, Markey added. Ensuring they can only play on your device with your permission and cutting off access to those in-game extra goodies may also help limit their game play.