You usually get 5 GB with free account, but currently there's an offer for 50 for LG users. Someone smarter than me figured out how to disguise your phone as an LG so you'll get 50 too, and I just tried it on my Samsung and it worked.
http://forum.xda-developers.com/showthread.php?t=1383808Short version: Download box.net app from market, back up your build.prop, modify the value in two linesto have following value, reboot, register on box app, restore the backup, reboot again.
ro.product.manufacturer=LGE
ro.product.model=VS910 4G
I'd imagine if too many people do this they'll patch the exploit, so get to it while you can.