Lovely hat.

Sale #1:

http://www.tf2outpost.com/trade/25588141

Sold for a Morning Glory Honcho's Headgear (78.5)

http://backpack.tf/profiles/76561198016958613?time=1428217200 (April 5th)

http://backpack.tf/profiles/76561198016958613?time=1428303600 (April 6th)

78.5 * 0.9 = 70.65, should be rounded to 70 keys

Sale #2:

Sold with a Searing YWN (~30-40?) + 1 bud (6) + 14 keys for a Burning Chieftain (84)

http://backpack.tf/profiles/76561198087212786?time=1428390000 (April 7th)

http://backpack.tf/profiles/76561198087212786?time=1428476400 (April 8th)

Chieftain: http://www.tf2outpost.com/trade/25632693

This is a bit complex, and the value for the Trophy Belt would probably come out under 40 keys. A definite outlier.