Sale 1:

Sold for 46 keys

Seller: https://backpack.tf/profiles/76561198141054773#!/compare/1529539200/1529625600

Buyer: https://backpack.tf/profiles/76561198232370220#!/compare/1529539200/1529625600

https://backpack.tf/item/3578561450

X = 46

Sale 2:

Sold for 40 keys + ~1 key in items

No outpost

Seller: https://backpack.tf/profiles/76561198088391137#!/compare/1532131200/1532217600

Buyer: https://backpack.tf/profiles/76561198110055031#!/compare/1532131200/1532217600

X = 41

Sale 3:

Sold for Duped Searing Plasma Le Party Phantom (Mini at 28 below) + ~2 keys in pure/items

No outpost

Seller: https://backpack.tf/profiles/76561198216561389#!/compare/1531440000/1531526400

Buyer: https://backpack.tf/profiles/76561198088391137#!/compare/1531440000/1531526400

X = 30

Sale 4:

Sold for 25 keys

Seller: https://backpack.tf/profiles/76561198337734785#!/compare/1533513600/1533600000

Buyer: https://backpack.tf/profiles/76561198205939253#!/compare/1533513600/1533600000

https://backpack.tf/item/4966784483

X = 25

Sale 5:

Sold for 25 keys

Seller: https://backpack.tf/profiles/76561198337734785#!/compare/1531440000/1533513600

Buyer: https://backpack.tf/profiles/76561198218497692#!/compare/1533427200/1533513600

https://backpack.tf/item/958814978

X = 25

Duped Searing Phantom Mini:

Sold for 28 keys

Seller: https://backpack.tf/profiles/76561198143680034#!/compare/1532044800/1532217600

Buyer: https://backpack.tf/profiles/76561197968968337#!/compare/1532131200/1532217600

https://backpack.tf/item/272821493

X = 28

Other Sales:

https://backpack.tf/item/4966784483 (#1 & #2)

https://backpack.tf/item/3578561450 (#3 & 4)

https://backpack.tf/item/958814978 (#5-8)

https://backpack.tf/item/6818120993 - Tradeit.gg stuff

https://backpack.tf/item/6468530157 - Mannco.trade stuff

https://backpack.tf/item/6045197649 - Marketplace.tf stuff

#1

Untraceable

https://backpack.tf/profiles/76561198204215085#!/compare/1532908800/1532995200

https://backpack.tf/profiles/76561198337734785#!/compare/1532908800/1532995200

#2

Sold with 9 keys for Kill-a-Watt Brown Bomber

https://backpack.tf/profiles/76561198110055031#!/compare/1532649600/1532736000

https://backpack.tf/profiles/76561198204215085#!/compare/1532736000/1536883200

Should be used on the bomber.

#3

Untraceable

https://backpack.tf/profiles/76561198232370220#!/compare/1529539200/1529625600

https://backpack.tf/profiles/76561198017534558#!/compare/1529539200/1529625600

#4

Bulk for 2 Haunted Ghosts TC’s

https://backpack.tf/profiles/76561198017534558#!/compare/1529884800/1529971200

https://backpack.tf/profiles/76561198160856661#!/compare/1529884800/1529971200

#5

Untraceable

https://backpack.tf/profiles/76561198115721685#!/compare/1530403200/1531440000

https://backpack.tf/profiles/76561198337734785#!/compare/1531353600/1531440000

#6

Bulk for Frostbite Dapper

https://backpack.tf/profiles/76561198218497692#!/compare/1533859200/1533945600

https://backpack.tf/profiles/76561198108020471#!/compare/1533859200/1533945600

#7

Bulk for Green Energy El Jefe

https://backpack.tf/profiles/76561198108020471#!/compare/1533859200/1533945600

https://backpack.tf/profiles/76561198255903931#!/compare/1533859200/1533945600

#8

Bulk for Beams Chill Chullo

https://backpack.tf/profiles/76561198255903931#!/compare/1534464000/1534550400

https://backpack.tf/profiles/76561198069825031#!/compare/1534291200/1534550400

Sellers:

https://i.imgur.com/YK9sTGK.png

https://backpack.tf/item/958814978 - 33 keys

https://backpack.tf/item/4974914613 - 34 keys

Sales at:

25 (2x)

30

41

46

Sales at 41 and 46 are clear outliers (and are probably wrong anyways), especially given the current sellers.

Going with 25-30.