Isn't it fun when so much... information, stems, from one suggestion? Such, knowledge...

Carouser mini:

http://www.tf2outpost.com/trade/20293152 B/O of 14 keys (5 days)

http://www.tf2outpost.com/trade/20292141 Sold for Bubbling Bootleg Billycock (15.5) + 4 keys

(15.5 * 0.9) + 4 = 17.95 (rounding to 18) (Possible outlier)

Histories:

http://www.tf2outpost.com/item/440,2675522933,259,5

http://www.tf2outpost.com/trade/20338328

http://www.tf2outpost.com/trade/19475241 Sold for Blizzardy Mongol (13.5)

13.5 * 0.9 = 12.15 (rounding to 12)

Histories:

http://www.tf2outpost.com/item/440,2675522933,259,5

http://www.tf2outpost.com/item/440,2595444124,313,5

18 is an outlier, using 12-14.