Sale 1:

Sold for $20 on Marketplace.tf

https://marketplace.tf/items/30618;5;u3008

Can't find item history

20/1.99 = ~10.05

X = 10

Sale 2:

Sold with ~0.5 keys in items for Blizzardy Storm Hetman's Headpiece

http://www.tf2outpost.com/trade/29589337 - B/O of 9

Seller: https://backpack.tf/profiles/76561198813270454#!/compare/1521244800/1521331200

Buyer: https://backpack.tf/profiles/76561198213917739#!/compare/1521244800/1521331200

Easily caps

X = 9 (Capped by B/O)

Sale 3:

Sold for 8 keys

Seller: https://backpack.tf/profiles/76561198105071091#!/compare/1520985600/1521072000

Buyer: https://backpack.tf/profiles/76561198813270454#!/compare/1520985600/1521072000

X = 8

Sale 4:

Sold for 6 keys + ~1 key in items

Seller: https://backpack.tf/profiles/76561198072240925#!/compare/1523059200/1523145600

Buyer: https://backpack.tf/profiles/76561197960719107#!/compare/1523059200/1523145600

X = 7

Sale 5:

Sold for 7 keys + small amount of ref (ID's match)

Seller: https://backpack.tf/profiles/76561198048851745#!/compare/1520640000/1520726400

Buyer: https://backpack.tf/profiles/76561198218968843#!/compare/1520467200/1520726400

X = 7

Sale 6:

Quicksold for 6 keys

Seller: https://backpack.tf/profiles/76561198133085500#!/compare/1520899200/1520985600

Buyer: https://backpack.tf/profiles/76561198105071091#!/compare/1520899200/1520985600

X = 6

Sale 7:

Sold for Isotope Well Worn Sniper Rifle

Seller: https://backpack.tf/profiles/76561198114545227#!/compare/1522713600/1522800000

Buyer: https://backpack.tf/profiles/76561198260247733#!/compare/1522713600/1522800000

yeah nah, not using this sale.

Sale 8:

Sold for Showstopper Headcase

Seller: https://backpack.tf/profiles/76561198063640894#!/compare/1524096000/1524182400

Buyer: https://backpack.tf/profiles/76561198120768380#!/compare/1524009600/1524182400

Probably better to use on the Headcase. Suggestion at 7 on it, so this would support that price.

Sale 9:

Sold with some items for Miami Nights Glengarry Bonnet

No outpost

Seller: https://backpack.tf/profiles/76561198218968843#!/compare/1520726400/1520899200

Buyer: https://backpack.tf/profiles/76561198133085500#!/compare/1520812800/1520899200

Will be way too high without a B/O cap, excluding.

Sale 10:

Bulk for Strange Purple Confetti Trucker's Topper

Seller: https://backpack.tf/profiles/76561198129255748#!/compare/1523750400/1524009600

Buyer: https://backpack.tf/profiles/76561198063640894#!/compare/1523923200/1524009600

Sale 11:

Bulk for Searing Dragonborn Helmet

Seller: https://backpack.tf/profiles/76561198807181411#!/compare/1522540800/1522627200

Buyer: https://backpack.tf/profiles/76561198072240925#!/compare/1522454400/1522540800

Sale 12:

Bulk for Pro. KS Vintage Lugermorph

Seller: https://backpack.tf/profiles/76561197960719107#!/compare/1523577600/1523664000

Buyer: https://backpack.tf/profiles/76561198057793695#!/compare/1523491200/1523577600

Sale 13:

Bulk for Miami Beret

Seller: https://backpack.tf/profiles/76561198310832681#!/compare/1520640000/1520726400

Buyer: https://backpack.tf/profiles/76561198050849650#!/compare/1520640000/1520726400

Sale 14:

Bulk for Time Warp Plug In Prospector

Seller: https://backpack.tf/profiles/76561198257062729#!/compare/1520380800/1520985600

Buyer: https://backpack.tf/profiles/76561198114545227#!/compare/1520899200/1520985600

Sale 15:

Bulk for Beams Pirate Bandana

Seller: https://backpack.tf/profiles/76561198362424197#!/compare/1519689600/1519776000

Buyer: https://backpack.tf/profiles/76561198053717045#!/compare/1519689600/1519776000

Sellers:

~5.04 keys:

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

https://backpack.tf/item/4557743967

~6.99 keys:

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

https://backpack.tf/item/4541749900

https://backpack.tf/item/4470348829

7 keys:

https://i.imgur.com/8wh0qNl.png

https://backpack.tf/item/6347792834

20 keys:

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

https://backpack.tf/item/5326122553

And another one on marketplace.tf for ~9 keys worth:

https://marketplace.tf/items/30618;5;u3008

SCM: (only the first 3 matter here)

https://i.imgur.com/yW45hox.png

$17.21 (~6.97 keys)

$17.82 (~7.21 keys)

$25.53 (~10.34 keys)

Sales at:

6

7 (2x)

8

9

10

May have to go with a bit of a range here. Every sale higher than 7 (except the mp.tf sale at 10) are over a month old, which is why they may seem high when compared to current sellers.

Seller at ~5 keys is selling for the same price as the highest quickbuyer, so I'll exclude that seller.

6 quicksold, but given the state of the classifieds, I'd say it's likely that the price will collapse and fall under 7 keys, so I'll keep 6 in the range.

Sale at 8 may seem high, but it's pure and there are several sales for higher that support it, so I'll keep 8 in the range.

Sale at 9 wasn't pure, and we can't determine the B/O of the sale at 10, so I'll exclude both of them.

Going with 6-8.