Slight tightening.

http://www.tf2outpost.com/trade/10092845 - Sold for NNB Little Buddy + White V Ten Gallon minus 1 key, about 16 keys with item and unusual overpay

http://www.tf2outpost.com/trade/9939111 - Rejected Bubbles Engi Cap (~16 with overpay)

http://www.tf2outpost.com/backpack/211048 - He bought one for a TS Bill's + Level 69 V Pyro Beanie (~14 keys or so)

Transaction:

http://i.imgur.com/Xy0iAbd.png

Lowest sale about 14 keys, rejected offer of 16, one in the middle, so that's 14-17.

Any extra proof, counters, comments, etc. are welcome.