3 in existence, 2 on market, I traded this hat 6 times in the past 2 weeks.

Sold with Steaming Glengarry Bonnet for DBD Capo's Capper. Pipe owner offered

Capper (2.6 buds) - Bonnet (1.1 bud) = Pipe (1.5 buds) = 23 keys

http://www.tf2outpost.com/trade/23456294#latest

http://www.tf2outpost.com/trade/23507317#latest

Sold with (Aussie Blutsauger + Festive Medigun + Conga) for (Pro KS SF Bat + Spec KS SF Knife)

http://i.imgur.com/Qf0dY0o.png?1

Pipe owner offered.

Pipe + 12 keys + 1.25 keys + 1 key = 19 keys + 14 keys

Pipe = 18.75 keys

Mini on Pro KS SF Bat:

http://www.tf2outpost.com/trade/23751787 19-20 keys. Cheapest anywhere

Sales this month on SCM shows an average of 16 keys, but I'm not sure if this is allowed as proof. I will use 19 keys as the reference. Whether 16 or 19 is used would not affect this range.

Mini on Spec KS SF Knife:

Multiple sales at 14 keys. Many sellers at 15 keys. Sales this month on SCM shows an average of 15 keys. I will use 14 as the reference.

http://www.trade.tf/classifieds/search/Sell/Strange/Festive%20Knife/all/Specialized%20Killstreak/1

Sold for 17.5 keys (keys were 10 ref at that time). Possible to round up to 18 keys.

http://i.imgur.com/AXto8F9.png?1

Sold for 14 keys. Quicksold to me. Outlier.

http://gyazo.com/4bef3575561bd50897b02ec1888a435e

Sold for bud + 3 keys = 18.5 keys (buds were 15.5 at the time)

http://gyazo.com/e5b9022d37094364ee1846a4cc313f1f

Sold for 16 keys. Quicksold to me. Outlier

http://gyazo.com/2aebb0873299c092a4825703aab13f5d

Sold for 18 keys. Note: it took me almost 2 weeks to sell this, with frequent bumps.

http://gyazo.com/9d9a2c0dfef35f08015fc5dc70946985

Sold with Villain's Veil for Flaming Lantern Hetman's Headpiece

Hetman (23 keys) - Veil (.4 keys) = Pipe (22.6 keys)

http://gyazo.com/977661919f29e9d6f50cb8ea1536e52c

Pipe owner offered.

Sold for Cloud 9 Cadaver's Cranium (25 keys).

http://gyazo.com/2747e8304391d1b04e8fef8db7772188

Cranium (25)*.9 = Pipe (22.5 keys)

Sold for 17 keys. Quicksold. I sold it in 3 hours. Outlier…ish.

http://gyazo.com/8d3b064e9fb92440cef4f86d5fe554c2

Sold with ~5 ref for Miami Defiant Spartan. Defiant Spartan is 1.5 - 2 buds. Using the low end (23 keys) would seem appropriate. Otherwise this sale would be an outlier (if valuing it at the mean price - 27 keys).

Spartan (23) - .45 keys (sweets) = Pipe (22.55 keys)

http://i.imgur.com/zTH6Mrl.png

Pipe owner offered.

Unsold at 26 keys (5 days, bumped, zero offers):

http://www.tf2outpost.com/trade/23739393

Seller at 25 keys (young):

http://www.tf2outpost.com/trade/23788998

^ These also prove why the Defiant Spartan would be an outlier if valued at the mean price.

Feel free to leave your thoughts.

Update (7 hours later):

The owner who was selling for 26 keys has changed his buyout to 20 keys.

Going to resuggest this, since the price needs to be in buds.