Item 1

https://backpack.tf/item/12180373665

Sale #1

Sold for 16 keys (ID "13075341003" of the unusual matches)-

Seller: https://backpack.tf/profiles/76561198850121720#!/compare/1684972800/1685059200

Buyer: https://backpack.tf/profiles/76561198856300150#!/compare/1676419200/1686960000

Item 2

https://backpack.tf/item/12296061684

Sale #2

Untraceable?-

Seller: https://backpack.tf/profiles/76561199128182851#!/compare/1684454400/1684540800

Buyer: https://backpack.tf/profiles/76561199107865875#!/compare/1684368000/1684454400

Sale #3

Bulk transfer-

Seller: https://backpack.tf/profiles/76561199107865875#!/compare/1686700800/1686787200

Buyer: https://backpack.tf/profiles/76561197963500354#!/compare/1686700800/1686787200

Item 3

https://backpack.tf/item/12186680381

Sale #4

Bulk transfer-

Seller: https://backpack.tf/profiles/76561199199711319#!/compare/1686700800/1692144000

Buyer: https://backpack.tf/profiles/76561198026129220#!/compare/1686700800/1686787200

Marketplace.tf Sales

https://marketplace.tf/items/tf2/30755;5;u265

MP.TF Sale #1

Sold for $40 on August 3, 2023

Keys @ $1.95

40/1.95 = 20.51ish keys

MP.TF Sale #2

Sold for $40 on August 7, 2023

Keys @ $2.05

40/2.05 = 19.51ish keys

Sales @ 16, 20, 21

Taking 16-21 here