I downloaded the Amazon Appstore to my Android tablet, because they give away a free app every day - apps that otherwise you'd have to pay for. There are quite a few apps that are incompatible with my tablet or just don't work properly on it, but I've downloaded some I like quite a bit, too. I downloaded a Sudoku game that I'm really enjoying. I never played it before, but it's nice on the tablet. There are different levels and instructions on how to play, which I needed. I'm still on the really easy ones, but I'm enjoying it.
Yesterday, I visited the Amazon Appstore for Android on my computer, instead of with the tablet, and discovered that I can get the apps right from my browser. So I can grab them while they're free, even if I don't have the tablet with me, and then download and install them later. I'm also thinking that maybe I'll be able to get apps that look promising, even if they're not compatible with my tablet, and then maybe be able to use them later, maybe when I upgrade my phone.
Then again, maybe not. By then, they'll probably be obsolete.
If you're not already using the Amazon Appstore, be sure to check it out. The free app of the day may be just the one you've been waiting for. And if not, there's always tomorrow!