Fully aware that I own one, price needs an update.

http://www.tf2outpost.com/trade/19486054

Sold for White Bill's (7 keys) + Scotsman's Skullcutter and CCC (5 keys, 4.5 with overpay) + 2 keys

13.5 (rounding to 14)

http://www.tf2outpost.com/trade/19477022

Sold for a Bill's (6 keys), 6 keys, 5 ref and 6.66 of items.

6 + 6 + 0.7 + 0.9 = 13.6 (rounding to 14)

On the market right now:

http://www.tf2outpost.com/trade/19016900 13 keys

http://www.tf2outpost.com/trade/19547604 No price set.

There are also a few others on the market, but they're duped and selling for 13 or 14 keys.

That's a 13 key seller for the low end and 2 sales at 13.5 for the high end. If you have additional proof or anything like that please let me know in the comments, thanks for reading through!

Edit: Just noticed I became an 'unusual expert', that's pretty cool to me :P