First suggestion, correct my mistake plz :D

Sales:

Phasewalker sold to Saving Ryan for 20 keys (near bottom has green check)

http://www.tf2outpost.com/trade/14042173

Buzz sold to EX0K for a for a Steaming The Hat With No Name (1.2 - 1.5)

http://www.tf2outpost.com/trade/14613145

http://backpack.tf/item/902316138

TMR sold to Mr.Vendingmachine for a Bubbling Honcho (1.2-1.3)

http://www.tf2outpost.com/trade/14971124

Mr.Vend's inv. Oct 10: http://backpack.tf/id/76561198027035689?time=1381647600

Mr.Vend's inv. Oct 13: http://backpack.tf/profiles/76561198027035689

TMR's inv Oct 13: http://backpack.tf/id/turhagep

^Just happened as I typed this apparently.

B/Os:

B/O was 1 bud, 3 weeks open (20 keys at time of post)

Probably sold for that.

http://www.tf2outpost.com/trade/14498680

B/o is 1.2, trade 1 week open:

Offers:

1. 16 keys + sweets, hidden.

http://www.tf2outpost.com/trade/14772350

B/O is 24 keys, trade open for a month.

A few offers:

1. smoking bonk helm (1-1.1 buds), hidden

2. stormy capotain (1-1.2), hidden

http://www.tf2outpost.com/trade/14313705

B/O is 22 keys, trade open 1 week.

Offers:

1. Bubbling Sola Topi + Sweets

2. spectral spectrum genuine dashin hashashin

3. Declined a bud

http://www.tf2outpost.com/trade/14808750

Old trades still open for 2 buds b/o

Trade up for 4 months with 2 bud b/o

http://www.tf2outpost.com/trade/10900399

Trade up for 5 months with 2 bud b/o

http://www.tf2outpost.com/trade/10306467

2 buds is too high apparently.

Conclusion:

Low is about 20 keys or 1.11, I don't see any trades or b/os under 20 keys and offers under are hidden.

High is 1.3 or about 23 keys because of trades for other unusual hats in that range. Anything over has gone open for months.

Hopefully I didn't get links mixed up. Surprised the suggested price is accurate after 6 months.