Earlier this month Amazon rolled out a new in-app purchase system for its Android store, and now it's already raised the upper limit that developers can charge for those purchases. In an email sent out to developers, Amazon said that, due to its recently upgraded parental controls, it now accepts items that cost more than $20. While Amazon's in-app purchases are typically one-click affairs, the new controls require either a password or PIN number — which should make it more difficult for kids to load up on smurfberries. Amazon users already spend more on in-app purchases than their Google Play counterparts and this latest news should put even more money in the bank.