Sale 1:

Sold with 25 keys for Scorching Translator (81)

Seller: https://backpack.tf/profiles/76561197963494936#!/compare/1557878400/1557964800

Buyer: https://backpack.tf/profiles/76561198193725573#!/compare/1557878400/1557964800

https://backpack.tf/item/7714101493

X = 56

Sale 2:

Sold for 46 keys

Seller: https://backpack.tf/profiles/76561198337734785#!/compare/1557792000/1557878400

Buyer: https://backpack.tf/profiles/76561197963494936#!/compare/1557532800/1557878400

https://backpack.tf/item/7714101493

X = 46

Sale 3:

Sold for 40 keys?

Seller: https://backpack.tf/profiles/76561198058326774#!/compare/1554768000/1554854400

Buyer: https://backpack.tf/profiles/76561198323624068#!/compare/1554768000/1554854400

https://backpack.tf/item/5117955623

Very clear on the buyer’s side, apart from the lack of history matching.

X = 40

Sale 4:

Sold to a quickbuyer for 37 keys + 1 rec

Seller: https://backpack.tf/profiles/76561198264858514#!/compare/1555632000/1555804800

Buyer: https://backpack.tf/profiles/76561198337734785#!/compare/1555718400/1555804800

https://backpack.tf/item/7714101493

X = 37

Other Sales:

https://backpack.tf/item/7714101493 (#1)

#1

Untraceable, only some keys match

https://backpack.tf/profiles/76561198193725573#!/compare/1559260800/1560211200

https://backpack.tf/profiles/76561198337734785#!/compare/1559779200/1559865600

#2

Untraceable

https://backpack.tf/profiles/76561198931837142#!/compare/1561334400/1561420800

https://backpack.tf/profiles/76561198357865695#!/compare/1560902400/1561420800

https://i.imgur.com/d689bNB.png - labelled as ~37 keys

The seller is most likely a scammer fence anyways.

Sellers:

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

https://backpack.tf/item/5997173220 - ~40 keys

https://backpack.tf/item/7714101493 - 45 keys

https://backpack.tf/item/7632632516 - 60 keys

https://backpack.tf/item/4403126726 - 60 keys

Sales at:

37

40

46

56

56 is a clear outlier, excluding.

Excluding 37 due to the current buyer at 37 https://i.imgur.com/BTHJoC4.png (subject to change, depending on what happens with the buyer, especially considering the high-end is fairly higher than the current sellers.)

Going with 40-46.