Re-suggesting, new range.

The Sale:

Sold for 11 keys

Seller: https://backpack.tf/profiles/76561198023542389#!/compare/1552262400/1552435200

Buyer: https://backpack.tf/profiles/76561198020834409#!/compare/1551830400/1552608000

https://backpack.tf/item/246496534

X = 11

Marketplace Sales:

https://marketplace.tf/items/104;5;u7

https://manic.tf/keyprice/?at=2019-01-21 - $26.7 / $1.75 = 15.26 keys

X = 15

Other Sales:

https://backpack.tf/item/240675917 (#1 & #3, excluded some gambling)

#1

Gambled

https://backpack.tf/profiles/76561198173381547#!/compare/1548633600/1548720000

https://backpack.tf/profiles/76561198875470056#!/compare/1548547200/1548720000

#2

Bulk for Ring of Fire Woolen Warmer

https://backpack.tf/profiles/76561198130834456#!/compare/1551830400/1551916800

https://backpack.tf/profiles/76561198120585187#!/compare/1551830400/1551916800

#3

Untraceable

https://backpack.tf/profiles/76561198120585187#!/compare/1552435200/1552521600

https://backpack.tf/profiles/76561198119149660#!/compare/1552435200/1552521600

Sellers:

https://i.imgur.com/CFJM3if.png

https://backpack.tf/item/240675917 - 13 keys

Sales at:

11

15

Little iffy on using the marketplace sale, especially given how long the seller of the sale at 11 had it for, though I couldn’t find anything that shows it was listed for that long, so I’ll wave it off this time.

New (spelled) seller at 13 further proves that 15 is an outlier. Excluding 15.

Going with 11 flat.