[quote name='Spyder187']DOTA 2 is free. just so you know.[/QUOTE]
It is free but there is still a waiting list. With this invite you don't have to wait. People may still want to play the CS:GO to try it out before buying.
I'd give you $5 for it. That even seems like a lot, considering the retail price is $15, and private beta is due to expire in 4 weeks or less in favor of an open beta.