Using last month.

Sale 1:

Sold for $15 on marketplace.tf

https://marketplace.tf/items/30614;5;u3007

15/1.98 = ~7.58

X = 7.5

Sale 2:

Sold for 5 keys + 10 ref

Seller: https://backpack.tf/profiles/76561198061108999#!/compare/1525478400/1525564800

Buyer: https://backpack.tf/profiles/76561198013137608#!/compare/1525564800/1525737600

X = 5.5

Sale 3:

Sold for 5 keys

Seller: https://backpack.tf/profiles/76561198054198170#!/compare/1523923200/1524009600

Buyer: https://backpack.tf/profiles/76561198384161769#!/compare/1523145600/1524009600

X = 5

Sale 4:

Quicksold for 4 keys + ~0.5 keys in metal/items

Seller: https://backpack.tf/profiles/76561198195731583#!/compare/1524096000/1524182400

Buyer: https://backpack.tf/profiles/76561198364127001#!/compare/1524096000/1524182400

X = 4.5

Sale 5:

Sold with a couple keys in items for Hellish Inferno Most Wanted

Seller: https://backpack.tf/profiles/76561198065959797#!/compare/1524873600/1525132800

Buyer: https://backpack.tf/profiles/76561198246068716#!/compare/1524700800/1524873600

Should be used on the Hellish one.

Sale 6:

Sold with Pro. KS Festive Medigun for Cyclone Stagger.

Seller: https://backpack.tf/profiles/76561198052999475#!/compare/1524873600/1524960000

Buyer: https://backpack.tf/profiles/76561198061108999#!/compare/1524873600/1524960000

Unless I can get the B/O on the Stagger from Blaze, this shouldn’t be used on either taunt. If the B/O fits well with the sellers on the Stagger, a second sale would still be needed, last time I checked.

Sellers:

~4.8 keys:

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

https://backpack.tf/item/3601562290

~5.3 keys:

http://www.tf2outpost.com/trade/29646277

~5.4 keys:

https://i.imgur.com/2v0WWOw.png

https://backpack.tf/item/4453775338

~5.5 keys:

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

https://backpack.tf/item/4967406789

~7.1 keys:

https://i.imgur.com/S5GjXAZ.png

https://backpack.tf/item/5105513845

10 keys:

https://i.imgur.com/3ZPNOCo.png

https://backpack.tf/item/4890365493

11 keys:

https://i.imgur.com/1FMrYDp.png

https://backpack.tf/item/4043848980

Offers:

http://www.tf2outpost.com/trade/29591965

Sales at:

4.5

5

5.5

7.5

7.5 is an outlier, excluding.

Would normally exclude 4.5 as it quicksold, but the seller at 4.8 supports a low-end lower than 5.

Going with 4.5-5.5.