This hat hasn't been updated in a while, and Chacha inspired me to do some research on the hat. Looks like the price range really does need to be updated. Proof below:

Sells Range 16 - 19.5 keys

http://www.tf2outpost.com/trade/9475685

- 15 keys + Diamond BK Sniper Rifle (4.5 keys)

- Based on the other offers for this hat, I do not believe this trade represents the current market. (based on rule #3 from suggestion guidelines). I'm only including it as I'm outlining all proof.

http://www.tf2outpost.com/trade/9399973

- Sold for 16 keys

Offers Range: 12-17

http://www.tf2outpost.com/trade/10623210 - Person is "quick selling" for 16 keys. Offered 17 keys in items (too hard to gauge what the actual offer is. Items are also typically overpay). Offered 12 keys

http://www.tf2outpost.com/trade/10545977 - Selling for Big Kill (14-15 keys), offered 6 keys

http://www.tf2outpost.com/trade/10394532 - Offered One Man Army w/Bubbling (13-16 keys) + some keys, 12 keys

http://www.tf2outpost.com/trade/10374858 - Offered 12 keys (same guy as other threads)

http://www.tf2outpost.com/trade/10112315 - Offered 12 keys (same guy as other threads)

http://www.tf2outpost.com/trade/10169087 - Offer of 15 keys

No offers

http://www.tf2outpost.com/trade/10393570 - No offers after 1 week

To note, all the 12 key offers were from the same person.