Sale 1:

Sold for $39.99 on Marketplace.tf

https://marketplace.tf/items/521;5;u58

https://backpack.tf/item/2352683308

39.99/1.9 = ~21.05

X = 21

Sale 2:

Sold for Blizzardy Boron (Mini at 10 below) + 6 keys

No outpost

Seller: https://backpack.tf/profiles/76561198220098345#!/compare/1508284800/1508803200

Buyer: https://backpack.tf/profiles/76561198126985704#!/compare/1508716800/1508803200

X = 16

Sale 3:

Sold for 15 keys

Seller: https://backpack.tf/profiles/76561198063640894#!/compare/1508198400/1508284800

Buyer: https://backpack.tf/profiles/76561198220098345#!/compare/1508198400/1508284800

X = 15

Sale 4:

Sold for Pro. KS Collector’s Holy Mackerel

Seller: https://backpack.tf/profiles/76561198126985704#!/compare/1508803200/1508889600

Buyer: https://backpack.tf/profiles/76561198125791160#!/compare/1508803200/1508889600

Pretty low. Not using.

Blizzardy Storm Pyro’s Boron Beanie Mini:

Sold for 10 keys

Seller: https://backpack.tf/profiles/76561198350044920#!/compare/1511136000/1511222400

Buyer: https://backpack.tf/profiles/76561198157523114#!/compare/1511136000/1511222400

X = 10

Sellers:

20 keys:

https://i.imgur.com/pfdEWoF.png - 1 month

https://i.imgur.com/M5g2MmY.png - 23 days

https://i.imgur.com/qZ8QiYw.png - 2 months

Sales at:

15

16

21

21 is too high, given the sellers at 20. Excluding 21.

Going with 15-16.