Using last month.

Sale 1:

Sold for $11.90 on marketplace.tf

https://marketplace.tf/items/30917;5;u3007

11.9/1.97 = ~6.04

X = 6

Sale 2:

Sold for 5 keys

Seller: https://backpack.tf/profiles/76561198305676157#!/compare/1524960000/1525046400

Buyer: https://backpack.tf/profiles/76561198043058406#!/compare/1524960000/1525046400

Bot.tf confirms: https://i.imgur.com/nSCr9C7.png

X = 5

Sale 3:

Sold for 5 keys

Seller: https://backpack.tf/profiles/76561198305676157#!/compare/1524268800/1524355200

Buyer: https://backpack.tf/profiles/76561198113038604#!/compare/1524355200/1524528000

1 key is missing but is linked below. Bot.tf confirms: https://i.imgur.com/nSCr9C7.png

https://backpack.tf/item/6796801039

https://backpack.tf/item/6796801051

https://backpack.tf/item/6796801073

https://backpack.tf/item/6796801087

https://backpack.tf/item/6796801097 - missing key, wasn’t scanned in buyer’s compare, but they would’ve got this key from selling the vintage lugermorph to the bot.

X = 5

Sale 4:

Bulk for some unusual pistol

Seller: https://backpack.tf/profiles/76561198074625962#!/compare/1523232000/1523318400

Buyer: https://backpack.tf/profiles/76561198022552163#!/compare/1523232000/1523318400

No current sellers, apart from the SCM ones that aren’t important here.

Sales at:

5 (2x)

6

Going with 5-6.