The current E3 digital ticket game bundle on HumbleBundle has 500 Amazon coins included at the $1 purchase level. 500 coins would cost you $4.90 to buy at Amazon so this is basically $5 worth of app purchases. You can get the bundle for as little as $1. Of course you can pay more if you want to donate to the charity in question too. There are some video game items too but it looks like "digital content" or downloadable content more than full games.
Note : Make sure you've got a good use for Amazon coins. Their app store doesn't have everything and theres plenty of free alternatives. Some of the games I like aren't on Amazon at all.
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