Sale 1:

Sold for Stormy Big Elfin Deal (9.5) + ’72 Results (4.5)

Seller: https://backpack.tf/profiles/76561198309838525#!/compare/1533686400/1533772800

Buyer: https://backpack.tf/profiles/76561198157176919#!/compare/1533686400/1533772800

https://backpack.tf/item/263600850

X = 14

Sale 2:

Sold for $27 on marketplace.tf

https://marketplace.tf/items/151;5;u12

https://backpack.tf/item/232749339 - No outpost

http://manicbot.me/keyprice/?at=2018-07-03 - 27/1.98 = ~13.64

X = 14

Sale 3:

Sold for Strange Festivized Scattergun + not much in other items

Seller: https://backpack.tf/profiles/76561198138117681#!/compare/1531526400/1532822400

Buyer: https://backpack.tf/profiles/76561198297000599#!/compare/1532736000/1532822400

https://backpack.tf/item/263600850

Sale 4:

Sold to a quickbuyer for some amount of keys

Seller: https://backpack.tf/profiles/76561198071896910#!/compare/1531180800/1531267200

Buyer: https://backpack.tf/profiles/76561198021272428#!/compare/1531180800/1531267200

https://backpack.tf/item/232749339

Sellers:

https://i.imgur.com/jksoe9t.png

14 keys:

https://backpack.tf/item/305341916

15 keys:

https://backpack.tf/item/232749339

Sales at:

14 (2x)

Going with 14 flat.