il start with the marketplace sales (as they were the least amount of work)

https://marketplace.tf/items/tf2/31085;5;u134

3x 99.99 at 1.87 a key = 53.47 keys

1x111.11 = 59.41 keys

now for the fun part.

sold for ??? (good luck)

https://backpack.tf/profiles/76561199186627182#!/compare/1634774400/1634860800

https://backpack.tf/profiles/76561198004290305#!/compare/1634774400/1634860800

sold for ? once again, hard to tell

https://backpack.tf/profiles/76561198044577564#!/compare/1635379200/1635897600

https://backpack.tf/profiles/76561199117306150#!/compare/1635465600/1635552000

bought for 53 in unusuals

https://backpack.tf/profiles/76561198846507621#!/compare/1633046400/1633219200

sold for 47 pure

https://backpack.tf/profiles/76561198846507621#!/compare/1633219200/1633824000

sold for Purple Energy Tippler's Tricorne plus 10 keys

https://backpack.tf/profiles/76561198012768468#!/compare/1635379200/1635552000

cash sale?

https://backpack.tf/profiles/76561198406114836#!/compare/1632787200/1632873600

https://backpack.tf/profiles/76561198170217781#!/compare/1632614400/1632873600

3x chain for this hat history

https://backpack.tf/item/8535037770

Large trade to the bot

https://backpack.tf/profiles/76561197964546925#!/compare/1634601600/1635120000

unlocatable from bot to abOod

https://backpack.tf/profiles/76561198106511423#!/compare/1634947200/1635120000

then to current owner in a large trade

https://backpack.tf/profiles/76561199193412191#!/compare/1635120000/1635206400

(out of date trade)

https://backpack.tf/profiles/76561199140888223#!/compare/1626566400/1627603200

classys have sellers at 52 and buyers at 49.

im gonna say the 59 key is an outlier and go with a 50 - 55 range

Thanks for coming to my TED talk