From another forum 
Quote
Free keys! https://bf3beta.battlefield.com/dob/index.php?id=1
Login and when asks for key, change in your adress field of browser "Key" to"legal"
Then press Enter and key is yours!
Login and when asks for key, change in your adress field of browser "Key" to"legal"
Then press Enter and key is yours!
Dammit, I guess this doesn't work anymore =(
I'd be willing to pay for a beta invite too!