To use VPN Master you don't need to have an account or identify yourself in any way. You just have to choose the app you want to use with VPN, and then start browsing. In the settings, you can change the country of the server you want to connect to, although in theory you shouldn't need to.
The free version of VPN Master lets you navigate for 200 megabytes, although you can increase this number in many ways. You can install other apps, or give a score to VPN Master to get more megabytes to browse. Or, of course, you can buy more with real money.
VPN Master is a very good VPN tool featuring an intuitive user interface, and in general is very easy to use.
Requires Android 4.0 or higher