Updating from the previous suggestion!

Sale #1

History: https://backpack.tf/item/6040879345

https://backpack.tf/profiles/76561199101711836#!/compare/1622937600/1623024000

https://backpack.tf/profiles/76561198236424352#!/compare/1622937600/1623024000

Sold for 82 keys and 26 ref(82.4), rounding to 82 keys

Sale #2

https://backpack.tf/profiles/76561199101711836#!/compare/1626652800/1626739200

https://backpack.tf/profiles/76561198140584551#!/compare/1626652800/1626739200

Sold for Genuine Robo-Sandvich(103 Keys)

Sale #3

https://backpack.tf/profiles/76561198064991263#!/compare/1626048000/1626134400

https://backpack.tf/profiles/76561198062420532#!/compare/1626134400/1626220800

Confirmed with the buyer for 97 Keys, rounding to 100 Keys

Sold for 100 Keys

Sale #4

https://backpack.tf/profiles/76561198146020362#!/compare/1620518400/1620604800

https://backpack.tf/profiles/76561198279054593#!/compare/1620518400/1620604800

New unbox, probably paypal scammed him like everyone else

Sale #5

https://backpack.tf/profiles/76561199124175531#!/compare/1620777600/1620864000

https://backpack.tf/profiles/76561198146020362#!/compare/1620777600/1620864000

Untraceable

Sale #6

https://backpack.tf/profiles/76561199124175531#!/compare/1622678400/1622764800

https://backpack.tf/profiles/76561198146020362#!/compare/1622592000/1622764800

Untraceable

Sale #7

https://backpack.tf/profiles/76561198060994353#!/compare/1618963200/1619049600

https://backpack.tf/profiles/76561198090147535#!/compare/1618963200/1619049600

Sold for Tesla Coil Salty Dog, using there

Marketplace sale

Item

$249.9 / $1.86 = 134.35, rounding to 135 Keys

Sold for 135 Keys

Sales at

82

100

103

135

Taking 100 - 135 Keys(avg. 117.5, rounding to 120 Keys) range here as per the previous suggestion. Thanks Xergoyf for the accurate range.