Using last month

Sale 1:

Sold with ~0.5 keys in metal for 7 keys

Seller: https://backpack.tf/profiles/76561198344933095#!/compare/1522713600/1522800000

Buyer: https://backpack.tf/profiles/76561198344933095#!/compare/1522713600/1522800000

Bot.tf kinda confirms: https://i.imgur.com/BxVeSeX.png

X = 6.5

Sale 2:

Sold for 3 keys + ~3.5 keys in items

No outpost

Seller: https://backpack.tf/profiles/76561198170456861#!/compare/1523145600/1523232000

Buyer: https://backpack.tf/profiles/76561198107215266#!/compare/1522713600/1523232000

X = 6.5

Sale 3:

Sold for $19.99 on Marketplace.tf

https://marketplace.tf/items/30572;5;u3008

Can't find item's history

Makes this ~10 keys, which will be an outlier compared to current sellers. Excluding.

Sellers:

6 keys:

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

https://backpack.tf/item/3922579071

~6.65 keys:

https://i.imgur.com/ka2yAu4.png

https://backpack.tf/item/6754577677

10 keys:

https://i.imgur.com/To1Jdpu.png

https://backpack.tf/item/6535806806

13 keys:

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

https://backpack.tf/item/5058377155

~20.45 keys:

https://i.imgur.com/VfP9dRz.png

https://backpack.tf/item/3942403374

Offers:

http://www.tf2outpost.com/trade/29552781

SCM: (Taking keys as $2.47)

https://i.imgur.com/YIw6Mql.png

$15.48 (~6.27 keys)

$17.25 (~6.98 keys)

$17.41 (~7.05 keys)

$22.11 (~8.95 keys)

$25.20 (~10.2 keys)

Sales at:

6.5 (2x)

Seller at 6 is currently too young to include, and is the only one at that price at the moment. Will wait to see if it sells.

Going with 6.5 flat.