Sale 1:

SCM Sale?

http://backpack.tf/profiles/76561198096045213#!/compare/1459814400/1460246400

Sale 2:

SCM Sale?

http://backpack.tf/profiles/76561198207631477#!/compare/1457164800/1457251200

Sale 3:

Sold with Orb Fire Larrikin for Aces Anger

http://backpack.tf/profiles/76561198147149994#!/compare/1457078400/1457164800

Better to update the Anger

Sale 4:

Sold for Terror-Watt Hat to Kill For + ~1 Key in taunts/ref

http://backpack.tf/profiles/76561198067008321#!/compare/1456732800/1456819200

x = 30.5 + 1

Rounding down to 31

Sale 5:

Sold for Terror-Watt Tavish Degroot

http://backpack.tf/profiles/76561198068585202#!/compare/1456646400/1456732800

x = ~20

Sale 6:

Sold for Ghosts Gatsby

http://backpack.tf/profiles/76561198086070401#!/compare/1461542400/1461628800

Mini on Gatsby

Sold for Kill-a-Watt Soldered Sensei

http://backpack.tf/profiles/76561198112612121#!/compare/1461369600/1461456000

Mini on Sensei

Sold for Spec Aussie Grenade

http://backpack.tf/profiles/76561198087962998#!/compare/1460764800/1460851200

x = 22

Sale 7:

Sold in a day for 25 Keys Pure - http://www.tf2outpost.com/trade/28139189

http://imgur.com/a/nsX3K

x = 25

Sale 8:

Sold with Peace Bonk Boy for AF Pom-Pommed + Terror-Watt Big Chief + 25 Keys

http://backpack.tf/profiles/76561198086070401#!/compare/1461024000/1461283200

Not using

Sale 9:

Sold for Spec KS Aussie Minigun

http://backpack.tf/profiles/76561198204104197#!/compare/1460937600/1461196800

x = ~22

Sale 10:

Sold for 23 Keys + TS Bill's + ~1 Key in Sweets

http://backpack.tf/profiles/76561198052694464#!/compare/1459728000/1459900800

x = 26

Conclusion:

Sales at 20, 22, 22, 25, 26, 31. Was tempted to call sales under 25 (since it quicksold for pure) outliers but too many sales in that range. Since 22, 25 and 26 sales were pretty much pure, going to call the lowest and highest sale outliers, taking a range of 22-26 Keys

Feedback is appreciated :D