Using last month.

Sale 1:

Sold for 14 keys

Seller: https://backpack.tf/profiles/76561198448505909#!/compare/1526083200/1526342400

Buyer: https://backpack.tf/profiles/76561198151387693#!/compare/1525564800/1526342400

Bot.tf confirms: https://i.imgur.com/sCcxTs5.png

X = 14

Sales 2 & 3:

Sold for $23 and $17 on marketplace.tf

https://marketplace.tf/items/30609;5;u3004

23/1.97 = ~11.7

17/1.98 = ~8.59

X = 12

X = 8.5

Sale 4:

Sold for 8 keys + 10 ref

Seller: https://backpack.tf/profiles/76561198305676157#!/compare/1526688000/1526774400

Buyer: https://backpack.tf/profiles/76561198101131482#!/compare/1526688000/1526774400

Bot.tf confirms: https://i.imgur.com/sCcxTs5.png

X = 8.5

Sale 5:

Sold to a bot for 6 keys + 5.11 ref

Seller: https://backpack.tf/profiles/76561198184303667#!/compare/1525478400/1525564800

Buyer: https://backpack.tf/profiles/76561198305676157#!/compare/1525478400/1525564800

Bot.tf confirms: https://i.imgur.com/sCcxTs5.png

X = 6

Sale 6:

Sold for 6 keys (buyer’s end)

Seller: https://backpack.tf/profiles/76561198239351878#!/compare/1525219200/1525305600

Buyer: https://backpack.tf/profiles/76561198124728984#!/compare/1525219200/1525305600

X = 6

Sales at:

6 (2x)

8.5 (2x)

12

14

14 seems too high given all the cheaper sales. Excluding 14.

6 looks a little low, excluding 6.

Going with 8.5-12.

2 sellers have appeared

https://i.imgur.com/z8TYptE.png

https://backpack.tf/item/5373837042

https://backpack.tf/item/3597990010