Item 1

https://backpack.tf/item/4771919831

Sale #1

Bulk sale-

Seller: https://backpack.tf/profiles/76561198311498888#!/compare/1686873600/1686960000

Buyer: https://backpack.tf/profiles/76561199069442401#!/compare/1686873600/1687132800

Item 2

https://backpack.tf/item/1497331915

Sale #2

Bulk transfer-

Seller: https://backpack.tf/profiles/76561199240976002#!/compare/1685750400/1686096000

Buyer: https://backpack.tf/profiles/76561199219758482#!/compare/1685404800/1685836800

Marketplace.tf Sales

https://marketplace.tf/items/tf2/1015;5;u3097

MP.TF Sale #1

Sold for $39.99 on May 27, 2023

Keys @ $2

39.99/2 = 20ish keys

MP.TF Sale #2

Sold for $39.99 on July 24, 2023

Keys @ $1.95

39.99/1.95 = 20.51ish keys

MP.TF Sale #3

Sold for $39.99 on August 1, 2023

Keys @ $1.95

39.99/1.95 = 20.51ish keys

Sales @ 20, 21, 21

Taking 20-21 here