When do people already in beta get beta keys for friends?

I have a group of online gamer buddies, one of them got into the beta and already used his available keys on the others and I'm sorta left out.. lol. But I was wondering when the next wave of beta keys for people already in beta can give to their friends.. is... (I'm hoping this made sense to you guys, sorry in advance if it was slightly hard to read!)

Or... you know, if someone has an extra one laying around... I'd accept a pm of it, lulz. :D

Edit: Got one, but would love a reply to the initial question still. Thanks in advance!

You got a key after 1 day of making your account? Lucky :(
Sorry I don't know... but my guess is that it's random