Using last month.

Sale 1:

Sold for Strange Pro. KS Frying Pan (~15)

http://www.tf2outpost.com/trade/29713686 - B/O of 11

Seller: https://backpack.tf/profiles/76561198145371132#!/compare/1531785600/1531872000

Buyer: https://backpack.tf/profiles/76561198157570330#!/compare/1531699200/1531785600

https://backpack.tf/item/2894250933

X = 11 (Capped by B/O)

Sale 2:

Sold for Aus SMG (~5.8) + Strange Festive Ambassador (~3 at the time)

http://www.tf2outpost.com/trade/29712757 - B/O of 9

Seller: https://backpack.tf/profiles/76561198049336546#!/compare/1531612800/1531699200

Buyer: https://backpack.tf/profiles/76561198161216801#!/compare/1531612800/1531699200

https://backpack.tf/item/6775354265

X = 9

Sale 3:

Sold with a key for Cyclone Trackman’s Touchdown (4.75) + Pro. KS Minigun (~5)

No outpost

Seller: https://backpack.tf/profiles/76561198126114757#!/compare/1533859200/1533945600

Buyer: https://backpack.tf/profiles/76561198807590356#!/compare/1533859200/1533945600

https://backpack.tf/item/6775354265

X = 9

Sale 4:

Sold for 8 keys + ~0.5 keys in cheap items

Seller: https://backpack.tf/profiles/76561198006544512#!/compare/1531699200/1531785600

Buyer: https://backpack.tf/profiles/76561198145371132#!/compare/1531699200/1531785600

https://backpack.tf/item/2894250933

X = 8.5

Sale 5:

Sold for $16.85 on marketplace.tf

https://marketplace.tf/items/1114;5;u3005

Can’t find item’s history

http://manicbot.me/keyprice/?at=2018-07-19

16.85/1.96 = ~8.6

X = 8.5

Sale 6:

Sold for 7 keys

Seller: https://backpack.tf/profiles/76561198334598690#!/compare/1532563200/1532649600

Buyer: https://backpack.tf/profiles/76561198094387902#!/compare/1528675200/1532649600

https://backpack.tf/item/5239919027

https://i.imgur.com/6Xae68Y.png

X = 7

Sale 7:

Sold for Pro. KS Backburner kit (~3) + ~3.5 keys in pure

No outpost

Seller: https://backpack.tf/profiles/76561198345578899#!/compare/1533513600/1533600000

Buyer: https://backpack.tf/profiles/76561198096697494#!/compare/1533600000/1534118400

https://backpack.tf/item/6922477944

X = 6.5

Sale 8:

Sold for 6 keys + 3 ref

Seller: https://backpack.tf/profiles/76561198830746853#!/compare/1531612800/1531699200

Buyer: https://backpack.tf/profiles/76561198426821785#!/compare/1531699200/1531872000

https://backpack.tf/item/5311837846

https://i.imgur.com/6Xae68Y.png

X = 6

Sale 9:

Sold with 18 ref (~0.5) for Whirlwind Buy a Life (5) + Spec. KS Scattergun (~1)

Seller: https://backpack.tf/profiles/76561198030481057#!/compare/1533340800/1533427200

Buyer: https://backpack.tf/profiles/76561198345578899#!/compare/1533340800/1533427200

https://backpack.tf/item/6922477944

X = 5.5

Sale 10:

Sold for 4 keys + 17 ref

Seller: https://backpack.tf/profiles/76561198263464269#!/compare/1532649600/1532736000

Buyer: https://backpack.tf/profiles/76561198030481057#!/compare/1532649600/1532736000

https://backpack.tf/item/6922477944

X = 4.5

Sale 11:

Bulk for Neutron Star Letch’s LED

Seller: https://backpack.tf/profiles/76561198055447337#!/compare/1531872000/1532131200

Buyer: https://backpack.tf/profiles/76561198136053973#!/compare/1532044800/1532131200

https://backpack.tf/item/6922477944

Sale 12:

Bulk for Peace Sign Safe’n’Sound

Seller: https://backpack.tf/profiles/76561198161216801#!/compare/1533081600/1533168000

Buyer: https://backpack.tf/profiles/76561198126114757#!/compare/1533081600/1533168000

https://backpack.tf/item/6775354265

Bot.tf stats state that there are 2 sales in the last month. Both of these sales are traceable, and occupy sales 6 and 8.

Sellers:

https://i.imgur.com/epbP0PP.png

8 keys:

https://backpack.tf/item/6922477944

9 keys:

https://backpack.tf/item/2860773869

https://backpack.tf/item/6345630907

https://backpack.tf/item/3978613684

https://backpack.tf/item/2690362406

15 keys:

https://backpack.tf/item/6775354265

Sales at:

4.5

5.5

6

6.5

7

8.5 (2x)

9 (2x)

11

4.5 looks like an outlier, does not appear to be a common trading point, and is pretty close to quickbuyers, excluding 4.5.

11 is an outlier, excluding 11.

9 is too high, given the 3 months unsold for 9 keys. Excluding 9.

Going with 5.5-8.5.

https://backpack.tf/profiles/76561198807590356#!/compare/1534377600/1534550400

https://backpack.tf/profiles/76561198204215085#!/compare/1534377600/1534464000

4 keys + ~0.5 keys in metal

only new sale.

Sold for 7 keys

https://backpack.tf/profiles/76561198011321852#!/compare/1535673600/1535760000

https://backpack.tf/profiles/76561198135114168#!/compare/1535328000/1535760000

https://backpack.tf/item/6345630907

Sold with Strange Big Topper for Hellish Inferno Yeti Smash

https://backpack.tf/profiles/76561198135114168#!/compare/1535846400/1535932800

https://backpack.tf/profiles/76561198145721198#!/compare/1535760000/1535932800

https://backpack.tf/item/6345630907

SCM

https://backpack.tf/profiles/76561198178204975#!/compare/1535155200/1535328000

https://backpack.tf/item/3452597732