Item 1

https://backpack.tf/item/11953754326

Sale #1

Bulk sale-

Seller: https://backpack.tf/profiles/76561198088057122#!/compare/1686787200/1686873600

Buyer: https://backpack.tf/profiles/76561198054270952#!/compare/1686787200/1686873600

Item 2

https://backpack.tf/item/11950296378

Sale #2

Bulk sale-

Seller: https://backpack.tf/profiles/76561198836883734#!/compare/1685577600/1685750400

Buyer: https://backpack.tf/profiles/76561198135388328#!/compare/1685664000/1685750400

Sale #3

Sold for 18 keys-

Seller: https://backpack.tf/profiles/76561198135388328#!/compare/1685750400/1685836800

Buyer: https://backpack.tf/profiles/76561197984823215#!/compare/1685577600/1685750400

Item 3

https://backpack.tf/item/11926274687

Sale #4

Sold for a Divine Desire Killing Tree (seems to low, not using here)-

Seller: https://backpack.tf/profiles/76561199072654974#!/compare/1683590400/1683676800

Buyer: https://backpack.tf/profiles/76561198353683794#!/compare/1683504000/1683763200

Marketplace.tf Sales

https://marketplace.tf/items/tf2/31271;5;u245

MP.TF Sale #1

Sold for $49.99 on June 6, 2023

Keys @ $1.98

49.99/1.98 = 25.25ish keys

MP.TF Sale #2

Sold for $49.99 on June 10, 2023

Keys @ $1.98

49.99/1.98 = 25.25ish keys

MP.TF Sale #3

Sold for $49.99 on August 1, 2023

Keys @ $1.95

49.99/1.95 = 25.64ish keys

Sales @ 18, 25, 25, 26

Taking 18-26 here