Sale 1:

Sold for 13 keys

Seller: https://backpack.tf/profiles/76561198181299287#!/compare/1524182400/1524268800

Buyer: https://backpack.tf/profiles/76561198128655858#!/compare/1524009600/1524268800

X = 13

Sale 2:

Sold for 13 keys

Seller: https://backpack.tf/profiles/76561198313538268#!/compare/1519344000/1519430400

Buyer: https://backpack.tf/profiles/76561198365967963#!/compare/1519344000/1519430400

Bot.tf confirms: https://i.imgur.com/e391eJX.png

X = 13

Sale 3:

Sold for 13 keys

Seller: https://backpack.tf/profiles/76561198349886701#!/compare/1520726400/1520812800

Buyer: https://backpack.tf/profiles/76561198122621946#!/compare/1520812800/1520899200

X = 13

Sale 4:

Sold for 13 keys

Seller: https://backpack.tf/profiles/76561198119568075#!/compare/1521936000/1522022400

Buyer: https://backpack.tf/profiles/76561198289285442#!/compare/1521072000/1522022400

X = 13

Sale 5:

Sold for 13 keys + 1 ref

Seller: https://backpack.tf/profiles/76561198349886701#!/compare/1522713600/1522800000

Buyer: https://backpack.tf/profiles/76561198135717209#!/compare/1522713600/1522800000

X = 13

Sale 6:

Sold for 13 keys + 2 ref

Seller: https://backpack.tf/profiles/76561198312583107#!/compare/1522972800/1523059200

Buyer: https://backpack.tf/profiles/76561198083673352#!/compare/1522972800/1523059200

Bot.tf confirms: https://i.imgur.com/e391eJX.png

X = 13

Sale 7:

Sold for 13 keys

Seller: https://backpack.tf/profiles/76561198308424086#!/compare/1524700800/1524787200

Buyer: https://backpack.tf/profiles/76561198074275586#!/compare/1524700800/1524787200

X = 13

Sale 8:

Sold for 12 keys + 16 ref

Seller: https://backpack.tf/profiles/76561198304138933#!/compare/1521158400/1521244800

Buyer can’t be traced: https://backpack.tf/item/1130847967

Bot.tf confirms: https://i.imgur.com/e391eJX.png

X = 13

Sale 9:

Sold to a bot for 11 keys + 16 ref

Seller: https://backpack.tf/profiles/76561198139434266#!/compare/1522713600/1522800000

Buyer: https://backpack.tf/profiles/76561198312583107#!/compare/1522713600/1522800000

Bot.tf confirms: https://i.imgur.com/e391eJX.png

X = 12

Sale 10:

Sold for 12 keys

Seller: https://backpack.tf/profiles/76561198302431811#!/compare/1520467200/1520640000

Buyer: https://backpack.tf/profiles/76561198106459677#!/compare/1520640000/1520726400

X = 12

Sale 11:

Sold for 12 keys

Seller: https://backpack.tf/profiles/76561198196677807#!/compare/1524614400/1524700800

Buyer: https://backpack.tf/profiles/76561198070635520#!/compare/1524614400/1524700800

X = 12

Sale 12:

Bulk for Max’s

Seller: https://backpack.tf/profiles/76561198122621946#!/compare/1521676800/1521763200

Buyer: https://backpack.tf/profiles/76561198119568075#!/compare/1521676800/1521763200

Sale 13:

Sold for an Unusual Revolver

No outpost

Seller: https://backpack.tf/profiles/76561198083673352#!/compare/1524182400/1524268800

Buyer: https://backpack.tf/profiles/76561198308424086#!/compare/1524182400/1524268800

Gonna be too high if used here.

Sale 14:

Sold for Haunted Ghosts Handle + ~2 keys in items

No outpost

Seller: https://backpack.tf/profiles/76561198365967963#!/compare/1519344000/1519430400

Buyer: https://backpack.tf/profiles/76561198058423925#!/compare/1519344000/1519430400

Gonna be a large outlier, excluding.

Sale 15:

Bulk for Cauldron Bubbles Stormin’ Norman

Seller: https://backpack.tf/profiles/76561198106459677#!/compare/1520640000/1520726400

Buyer: https://backpack.tf/profiles/76561198079578383#!/compare/1520640000/1520726400

Sale 16:

Sold for Orbiting Fire Hottie’s Hoodie

No outpost

Seller: https://backpack.tf/profiles/76561198376244015#!/compare/1523750400/1523836800

Buyer: https://backpack.tf/profiles/76561198102014780#!/compare/1523750400/1523836800

Way too high here, way too low there. Excluding.

Sellers:

14 keys:

https://i.imgur.com/0M80w3L.png

https://backpack.tf/item/959262630

https://backpack.tf/item/868253288

Sales at:

12 (3x)

13 (8x)

Going with 12-13.