This app was mentioned in 2 comments, with an average of 2.50 upvotes
I personally use SurfEasy and VyprVPN. They both require easy signups and have 500MB caps (SurfEasy can get bumped to 1.5 GB with a little effort) though. Still adequate for mobile use.
Pre-mention warning: Don't use Hola. It's been revealed as a botnet.
Edit: Who the fuck had the bright idea to put autocorrect on OSX?!
Which app store? Troubles seeing the $12.99.
Android https://play.google.com/store/apps/details?id=com.surfeasy
iTunes https://itunes.apple.com/us/app/surfeasy-vpn/id633495655?mt=8
Personally, I signed on with my laptop and got the 5 device version. Then just got the app and signed on to my 5 device account.
They may be quoting you the 5 device Ultra tier ($11.99), but you get a 46% discount if you buy the annual plan ($6.49). The cheaper total plan is sufficient for most users.