Sale 1:

Bought from Scrap.tf for 9 keys

https://backpack.tf/profiles/76561198135388328#!/compare/1702080000/1702166400 - Near ID: 13895747925

https://backpack.tf/profiles/76561197994176164#!/compare/1670889600/1703116800

https://backpack.tf/item/11097034122

= 9 keys

Sale 2:

Bought from Scrap.tf again for 9 keys

https://backpack.tf/profiles/76561198135388328#!/compare/1701561600/1701648000

https://backpack.tf/profiles/76561198834092605#!/compare/1673049600/1701648000

https://backpack.tf/item/9576147318

= 9 keys

Other Sales:

#1

https://backpack.tf/profiles/76561198002545389#!/compare/1701302400/1701388800

https://backpack.tf/profiles/76561198244962432#!/compare/1701302400/1701388800

https://backpack.tf/item/13049160956

Bulk for Haunted Ghosts Voodoo JuJu

#2

https://backpack.tf/profiles/76561198066307477#!/compare/1703203200/1703548800

https://backpack.tf/profiles/76561198013207659#!/compare/1703376000/1703548800

https://backpack.tf/item/10262388648

Untraceable

#3

https://backpack.tf/profiles/76561198135388328#!/compare/1703116800/1703203200

https://backpack.tf/profiles/76561199564942025#!/compare/1703116800/1703203200

https://backpack.tf/item/9594092523

Untraceable Scrap.tf purchase. Most likely missing a person in history.

https://backpack.tf/item/11116432999 - wasn't unusual until after traded

Marketplace Sales:

https://marketplace.tf/items/tf2/31162;5;u3003

$24.99, December 1st

This will end up being around 14-15 keys. Not using, will show why later.

Sellers/Buyers:

https://imgur.com/a/9Rh56Pj

https://backpack.tf/item/11576240901 - ~10.5 keys

Sales at:

9 (2x)

+ the marketplace sale at ~14-15 keys.

The marketplace sale is, not only an outlier, but is directly countered by the seller at 10 keys, which has remained there for at least a month.

https://next.backpack.tf/classifieds/snapshots/Holy%20Grail%20Taunt:%20The%20Fist%20Bump/6566c3d6e720e09657058099 - November 29th, ~10.2 keys

https://next.backpack.tf/classifieds/snapshots/Holy%20Grail%20Taunt:%20The%20Fist%20Bump/6571ea2973d409a478226171 - December 8th, ~10.2 keys

https://next.backpack.tf/classifieds/snapshots/Holy%20Grail%20Taunt:%20The%20Fist%20Bump/65823df1205fec2681076131 - December 20th, ~9.7 keys

Excluding the marketplace sale.

Going with 9 flat.