Because proof is rather long and I feel lazy, I'll just copypaste what polar bear said.

1 of 3, 2 on the market.

Overpay is applied.

http://www.tf2outpost.com/trade/13980803

Added an O. Fire Hallmark (~1.8 buds) and 14 keys for a Cloudy Moon Bicorne (~12.6 buds)

~10.1 buds

http://backpack.tf/id/76561198060902255?time=1377068400 and http://backpack.tf/id/76561198060902255?time=1377932400

http://www.tf2outpost.com/trade/14285321

Added 2.6 buds for a Burning Bicorne (~13 buds)

~10.4 buds

http://backpack.tf/id/76561198060902255?time=1379055600 and http://backpack.tf/id/76561198060902255?time=1379142000

http://www.tf2outpost.com/trade/10885531

Unboxer, offered $300 (~8.3 buds) + Max's Head - repless, apparently new(?) account, not valid.

"Burning bicorne is a dupe and is not 13, especially since that price you have there is inflated and based on the clean ones

Moon bicorne is clean and original price on that was 10.5-13.3. He did the offering, so no overpay. That sale would still come out to ~9.5.

As for the other sale, i wouldn't value the burning bicorne more than 12 since even a clean one is selling for 13 - http://www.tf2outpost.com/trade/14463017

http://www.tf2outpost.com/trade/10885531 - 8 pure was probably close for him and is the best thing after 4 months of selling

http://www.tf2outpost.com/trade/13756565 - time warp coldkiller + 1 ~8.6 after overpay

Range shouldn't be higher than 8.6-9.5"