Team Fortress 2
Counter-Strike: Global Offensive
Only 2 recent sales I could find
Sale 1: (from last suggestion)
sold for a aussie rl 43k
http://www.tf2outpost.com/trade/29222134 Caps a B/O of 33 keys
(credits to 13.t)
Sold for 35 pure
This is more of a fix as the last suggestion got my purchase wrong due to me using keys I only just got that day.
Both sales are slightly older than 3 months but they are also the only recent sales I could find.
Let me know if there's more or that these sales are too old to use.