The Amazon Appstore hasn't exactly grown to rival Google Play in size or overall quality, but there's still some cool stuff over there. And if you can get it for free? That's a pretty good deal. Amazon is offering $5 to spend on apps and all you have to do is download something.
Starting on December 24th and running through the 28th, anyone who downloads an app or game using the latest version of the Amazon Appstore client will get a $5 credit to spend on Appstore content.