Dota 2 beta?

There is people with tradeable copies, and I don't think you can get it in another way.

It it still possible. You can possibly still take the survey, but other then that you can trade for / win an invite. (Please don't trade here, go to steamtrades ).

DotA poll steam://takesurvey/1

thousands of trade offers are on playdota.com forum

The Survey is the only real free chance to get a hold of this but there's a couple of copies of DOTA 2 per day available for trade on http://www.reddit.com/r/SteamGameSwap/ and failing that you can always buy a copy for around $20 on http://www.reddit.com/r/SteamSell/ but remember it's a bit of a gamble considering the game could be released any day now.