This worked for me without root some time ago but it might still work.

Once you set up your account install this apk

http://www.mediafire.com/?6uzjl6hjtxtindl

Put in your account info and then hit the free 50g tab below it.

Then I checked and my 50g were there on my account. After that I
Changed the password on my account just to be safe.

I did this via my xoom fe by the way.

Good luck and let use know if this still works.

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