Using this suggestion as a demonstration for challenge but nothing should be wrong with it I hope!

Item 1

https://backpack.tf/item/13118723409

Ignoring the transfer from owner to bot

Sale #1

Untraceable?-

Seller: https://backpack.tf/profiles/76561198311498888#!/compare/1699142400/1699228800

Buyer: https://backpack.tf/profiles/76561199127773728#!/compare/1699228800/1699315200

Sale #2

Untraceable bulk sale?-

Seller: https://backpack.tf/profiles/76561199127773728#!/compare/1699315200/1699401600

Buyer: https://backpack.tf/profiles/76561199177136435#!/compare/1699315200/1699401600

Sale #3

Sold for 41 keys (ID "13895313009" of the unusual matches)-

Seller: https://backpack.tf/profiles/76561199177136435#!/compare/1702080000/1702166400

Buyer: https://backpack.tf/profiles/76561198145331385#!/compare/1702080000/1702166400

Item 2

https://backpack.tf/item/12060200372

Ignoring the multiple transfers that happened here between bot and owner

Sale #4

Sold for 53 keys (ID "13895305365" of the unusual matches)-

Seller: https://backpack.tf/profiles/76561199240976002#!/compare/1702080000/1702166400

Buyer: https://backpack.tf/profiles/76561198145331385#!/compare/1702080000/1702166400

Item 3

https://backpack.tf/item/11441506698

Ignoring both transfers between bot and owner

Sale #5

Sold for 52 keys (ID "13869437215" of the unusual matches)-

Seller: https://backpack.tf/profiles/76561198054270952#!/compare/1701648000/1701734400

Buyer: https://backpack.tf/profiles/76561199111648936#!/compare/1701648000/1701734400

Sale #6

Some keys do trace leaving the buyer's side but not enough show up to count this above buyers, incomplete and untraceable-

Seller: https://backpack.tf/profiles/76561199111648936#!/compare/1701648000/1701734400

Buyer: https://backpack.tf/profiles/76561199139085248#!/compare/1701734400/1701820800

Sale #7

Sold for 53 keys (ID "13895314208" of the unusual matches)-

Seller: https://backpack.tf/profiles/76561199139085248#!/compare/1702080000/1702166400

Buyer: https://backpack.tf/profiles/76561198145331385#!/compare/1702080000/1702166400

Item 4

https://backpack.tf/item/7957179742

Ignoring the transfer between owner to bot

Sale #8

Sold for 49 keys (keys in the bulk match histories)-

Seller: https://backpack.tf/profiles/76561198188093413#!/compare/1695945600/1696032000

Buyer: https://backpack.tf/profiles/76561198337734785#!/compare/1695945600/1696032000

Sale #9

Sold for 53 keys (ID "13895308442" of the unusual matches)-

Seller: https://backpack.tf/profiles/76561198337734785#!/compare/1702080000/1702166400

Buyer: https://backpack.tf/profiles/76561198145331385#!/compare/1702080000/1702166400

Item 5

https://backpack.tf/item/7956364073

Sale #10

Sold for 49 keys + 39.66 refined (keys in the bulk match histories)-

Seller: https://backpack.tf/profiles/76561199111648936#!/compare/1696204800/1696291200

Buyer: https://backpack.tf/profiles/76561198337734785#!/compare/1696204800/1696291200

Item 6

https://backpack.tf/item/3324894558

Ignoring the transfer from bot to owner here

Sale #11

ID "13870762908" of the unusual matches to only 50 refined, incomplete-

Seller: https://backpack.tf/profiles/76561198135809649#!/compare/1699401600/1701734400

Buyer: https://backpack.tf/profiles/76561199192088525#!/compare/1701648000/1701734400

MP.TF Sale #1

Sold for $149.90 on December 25, 2023

Average Key Price @ $1.67ish

149.90/1.67 = 89.76ish keys

https://backpack.tf/item/3324894558

https://marketplace.tf/items/tf2/778;5;u58

Sales @ 41, 49, 50, 52, 53, 53, 53, 90

Taking 90 flat :3