https://backpack.tf/item/1651787459

Sale 1) Bulk sale

https://backpack.tf/profiles/76561198450549876#!/compare/1616544000/1616630400

https://backpack.tf/profiles/76561198081129776#!/compare/1616544000/1616630400

Sale 2) Sold for a Scorching Flames King Cardbeard + 6 Keys

https://backpack.tf/profiles/76561198136017741#!/compare/1616630400/1616716800

https://backpack.tf/profiles/76561198397507022#!/compare/1616630400/1616716800

As the Cardbeard was immediately dumped for 47 Keys, this sale can be treated as 53 Keys

https://backpack.tf/item/1693986932

Sale 3) Bulk sale

https://backpack.tf/profiles/76561197994697258#!/compare/1612569600/1612656000

Sale 4) Sold + 3 Keys for a Photons Globetrotter (50 Keys) + Cool FT Alpine Minigun

https://backpack.tf/profiles/76561197994697258#!/compare/1614470400/1614556800

https://backpack.tf/profiles/76561198880428283#!/compare/1613692800/1614556800

Excluding since the buyer dumped the Buddy for much less in Sale 5.

Sale 5) Sold for 43 Keys

https://backpack.tf/profiles/76561199066831021#!/compare/1616630400/1616716800

Excluding since the buyer in Sale 4 dumped the Buddy for much less.

Sale 6) Sold for 70 Keys

https://backpack.tf/profiles/76561199066831021#!/compare/1617062400/1617148800 - 27 Keys here

https://backpack.tf/profiles/76561198062329277#!/compare/1617062400/1617148800 - 43 Keys for the Cotton

Sale 7) ?

https://backpack.tf/profiles/76561198281724317#!/compare/1617580800/1617753600

https://backpack.tf/profiles/76561198121582224#!/compare/1617580800/1617753600

Sale 8) Sold for $105 when Keys were ~$1.95 each

https://mannco.store/item/33537

105 / 1.95 = 53.84, which rounds to 54 Keys

ty shuffle!