Re-suggesting, still using last month.

Sale 1:

Sold for 7 keys

Seller: https://backpack.tf/profiles/76561198344933095#!/compare/1523664000/1523750400

Buyer: https://backpack.tf/profiles/76561198412292295#!/compare/1523664000/1523750400

Bot.tf confirms: https://i.imgur.com/Yh15Jqc.png

X = 7

Sale 2:

Sold for 6 keys + 16 ref

Seller: https://backpack.tf/profiles/76561198021055079#!/compare/1525219200/1525305600

Buyer: https://backpack.tf/profiles/76561198172127891#!/compare/1525305600/1525392000

X = 6.5

Sales 3 & 4:

Sold for $11.5 and $7 on Marketplace.tf

https://marketplace.tf/items/1114;5;u3010

There’s currently a mp.tf buy order at $7, so I’ll exclude that.

11.5/1.97 = ~5.84

X = 6

Sale 5:

Sold for 5 keys

Seller: https://backpack.tf/profiles/76561198302093156#!/compare/1524700800/1524873600

Buyer: https://backpack.tf/profiles/76561198283343309#!/compare/1524787200/1524873600

X = 5

Sale 6:

Sold for Kill-a-Watt Hard Counter

No outpost

Seller: https://backpack.tf/profiles/76561198196459527#!/compare/1522886400/1522972800

Buyer: https://backpack.tf/profiles/76561198104929314#!/compare/1522886400/1522972800

Gonna be pretty high compared to other sales. Excluding.

Sale 7:

Sold for Silver Cyclone Bad Pipes

Seller: https://backpack.tf/profiles/76561198400887460#!/compare/1524009600/1525219200

Buyer: https://backpack.tf/profiles/76561198021055079#!/compare/1523923200/1524009600

Bad pipes were updated to ~6.75 recently, but there’s now a seller at 4.5, so I’ll exclude it for now. Even if it were used, it'll end up in the price range.

Sellers:

6 keys:

https://i.imgur.com/zThnQuH.png

https://backpack.tf/item/2715599883

~6.7 keys:

https://i.imgur.com/tZiCuem.png

https://backpack.tf/item/2805187228

https://backpack.tf/item/5280320158

https://i.imgur.com/ieQmvlT.png

https://backpack.tf/item/3551561175

8 keys:

http://www.tf2outpost.com/trade/29603200

10 keys:

https://i.imgur.com/Qj9dvUP.png

https://backpack.tf/item/3974858346

13 keys:

https://i.imgur.com/6sHXEek.png

https://backpack.tf/item/6417897231

14 keys:

https://i.imgur.com/jD4buee.png

https://backpack.tf/item/2828281719

20 keys:

https://i.imgur.com/fADrgD1.png

https://backpack.tf/item/3789828788

https://i.imgur.com/jTQq5y7.png

https://i.imgur.com/fEQ6MAh.png

https://backpack.tf/item/6460468661

https://backpack.tf/item/5305523691

23 keys:

https://i.imgur.com/PH5d7YQ.png

https://backpack.tf/item/6633806401

Sales at:

5

6

6.5

7

I had originally excluded 7 as it looked like an outlier with the cheaper sellers, but the amount of sellers lower than this sale has slightly reduced, and we now have stronger support for the high-end.

Going with 5-7.