Seriously the first thing I would get on iOS is App Shopper, I have gotten literally hundreds of games for free from it. Popular->Price Drops->Filter to free. That's it, not very hard to track daily.
Speaking of games free, Sonic Jump was free this morning, it seems pretty good for a Doodle Jump clone.
I have been enjoying this stupid F2P game Happy Street but I suddenly need moon stones and the full moon never seems to appear. So game has gone from stress relief to stress inducing until I get over that bump. The game is better than most F2P games and has some funny one liners here and there, I am sure it has been pimped here before but only a few people from GAF seems to be playing it seriously. Don't buy Flooz, you don't seem to have to to unlock most of the game - you just need patience...
Speaking of F2P - CSR Racing is pretty fun as stress relief as well but I bet they did enough math to always make it so you barely don't have enough coins to buy cars every tier upgrade, I am about to move to Tier 3 and have 17 coins but it is probably not enough to buy a car and I don't feel like grinding to buy one with cash, so it is like the trick of "oh now you are hooked on this game and you want a cool car, either spend 5 hours grinding or pay up buster"