If you like games, you can install Buzz Killem on your iOS device. With this game, you play a retired war veteran, called into action to fight against Aliens who are checking out Earth. You get to defend the Statue of Liberty and fight at Grand Central Station. There are multiple levels, retro-graphics and plenty of unlockables to keep your interest. Normally $1.99, Buzz Killem is free right now, from the app store.
The third free app is iScanner, which turns your iOS device into a...scanner. Documents can be kept as PDFs or JPG files. You can sync scans between devices, and email or print them with just one click. Normally priced at...you got it, $1.99, iScanner is currently free. If you do a lot of work with documents, this could be a very productive app for you to install.
Pick up all three apps for free, costing you nothing but some of the storage space on your iPhone or iPad.
source: WeatherDial, iScanner, BuzzKillem via BGR