5 6 failed suggestions, let's try this one again.

http://www.tf2outpost.com/trade/14109736 - no B/O

http://www.tf2outpost.com/trade/13224047 - sold for Roboactive Front Runner (7.4–9.4 buds)

http://backpack.tf/classifieds/search/id/520054fc4bd7b8bf3600001e - 5 buds seller ( http://www.tf2outpost.com/trade/14018628 selling for 6 buds, he bought it from a phisher for 4 buds)

http://www.tf2outpost.com/trade/12811515 - Phosphorus Bubble Pipe sold for smoking gibus, 4 keys, strange grenade, black fl, lime, black paint (no price)

http://www.tf2outpost.com/trade/13603580 - probably sold for Clean level 59 Max w/ Spectral Spectrum (2.2 buds + 9 keys) + 2 buds + sweets = 4.6 buds (outlier)

http://www.tf2outpost.com/trade/13093250 - Sold in combination with some sweets for Flies Fruit Shoot (7.6–9 buds - 4 months old price)

http://www.tf2outpost.com/trade/12332484 - quicksold for 4 buds

http://www.tf2outpost.com/trade/12342431 - Selling for 6 buds (check comments)

http://www.tf2outpost.com/trade/12602877 - Burning flames Cone offer (5.1–5.6 buds)

http://www.tf2outpost.com/trade/12603381 - (duped) Moon Buto (21.2–23.9 buds) for Power Surge War Pig (8.4–8.6 buds) + Smoking Gibus + 3 buds (some random blind bear...) Gibus: 9.8-12.3 buds. Yet the Buto was duped, so the value of the Gibus is probably a bit lower.

http://www.tf2outpost.com/trade/13267446

Sold Gibus + 1 bud + G fetti Softcap (17–20 keys) + Heart Trilby (3.6–4 buds) + stormy toque (21–24 keys) for Cloudy Moon Stahlhelm (13.6–16.3 buds)

Before trade: http://backpack.tf/id/76561197995915986?time=1375945200

After trade: http://backpack.tf/id/76561197995915986?time=1376290800

Gibus= ~7.4 buds with overpay.

The price:

6 buds as lower. There is a buyout that is less, yet this hat has been hijacked and sold for 4, the current owner tries to quicksell it for 5 buds. I'm not including this price. 6 buds is because one seller wanted to go that low.

7.6 buds as upper because of fruit shoot sale + other 2 sales.

-- Thanks blind polar bear --