Team Fortress 2
Counter-Strike: Global Offensive
Comments can no longer be left on this suggestion.
Sold for Spec. KS Aussie Grenade Launcher (~13.5) + ~4 keys in items
http://www.tf2outpost.com/trade/29320469 - B/O of 17
X = 17 (Capped by B/O)
Sold for 15 keys (Buyer's compare link)
X = 15
No current sellers (despite belonging to an unusual bot)
Going with 15-17.