Sale 1:

Sold for Kill-a-Watt Tough Stuff Muffs (32.5)

http://www.tf2outpost.com/trade/29241586 - B/O of 30

Seller: https://backpack.tf/profiles/76561198075435735#!/compare/1502150400/1502236800

Buyer: https://backpack.tf/profiles/76561198388803476#!/compare/1502150400/1502236800

X = 30 (Capped by B/O)

Sale 2:

Sold for Steaming Gentleman’s Ushanka (14) + Searing Plasma Dread Knot (Suggestion at 9.5) + ~2.5 keys in items

No outpost

Seller: https://backpack.tf/profiles/76561198236985112#!/compare/1503446400/1503532800

Buyer: https://backpack.tf/profiles/76561198024332838#!/compare/1503446400/1503532800

X = 26

Sale 3:

Sold for 23 keys + <0.5 keys in items

No outpost

Seller: https://backpack.tf/profiles/76561198313582232#!/compare/1502928000/1503014400

Buyer: https://backpack.tf/profiles/76561198236985112#!/compare/1502841600/1502928000

X = 23

Sale 4:

Quicksold for 20 keys

No outpost

Seller: https://backpack.tf/profiles/76561198053218438#!/compare/1502150400/1502236800

Buyer: https://backpack.tf/profiles/76561198313582232#!/compare/1502064000/1502236800

X = 20

Sale 5:

Sold for Stormy Bot Dogger + Blizzardy Scotch Bonnet

http://www.tf2outpost.com/trade/29218157 - B/O of 25

Seller: https://backpack.tf/profiles/76561198251043990#!/compare/1496793600/1496966400

Buyer: https://backpack.tf/profiles/76561197999845696#!/compare/1496880000/1496966400

Should cap at the B/O, or at least fall in the range.

Sale 6:

Bulk for Steaming Nunhood

Seller: https://backpack.tf/profiles/76561198168863803#!/compare/1500595200/1500681600

Buyer: https://backpack.tf/profiles/76561198087172601#!/compare/1500508800/1500681600

Searing Plasma Dread Knot:

https://backpack.tf/suggestion/599fe5bdcf6c750df2183ece

Sellers:

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

Sales at:

20

23

26

30

And another sale at ~25.

20 quicksold, and buyer at 20. Excluding 20.

30 looks like an outlier, and took about a year to sell. Excluding 30.

Going with 23-26.