Own a Nexus 4? Want to claim your Box 50GB? Just log into Box for Android on your device before December 31, 2012. If you don’t have a Box account yet, be sure to download the app on device. You’ll have 50GB of free, secure file storage and sharing for the life of your account.
Back in November 2011, Box announced...
We're excited to announce that we’ve teamed up with LG to offer free 50GB Box Personal accounts on all LG phones and tablets in the U.S. running Android OS 2.1 and above (with display resolution of 320×480 or higher).
So that's US only then? Actually no... because the Nexus 4 is registered as a US Device with the FCC (Federal Communications Commission), any Nexus 4 owner anywhere in the world can benefit from the 50GB for life offer!
All you need to do is download the app from the Play Store and register for the service as Zarch1972 confirms:
Bear in mind that although the free account has 50GB of storage, the individual file size is limited to 100MB. So you're not going to be putting your movies up there. :)