Using last month.

Sale 1:

Sold for 13 keys

Seller: https://backpack.tf/profiles/76561198335791307#!/compare/1537488000/1537574400

Buyer: https://backpack.tf/profiles/76561198105359319#!/compare/1537401600/1537488000

https://backpack.tf/item/2908561038

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

X = 13

Sale 2:

Sold for 9 keys

Seller: https://backpack.tf/profiles/76561198002757046#!/compare/1537228800/1537315200

Buyer: https://backpack.tf/profiles/76561198027338258#!/compare/1537142400/1537315200

https://backpack.tf/item/2753312534

X = 9

Sale 3:

Sold for 8 keys + ~1 key in metal

Seller: https://backpack.tf/profiles/76561198305676157#!/compare/1539129600/1539216000

Buyer: https://backpack.tf/profiles/76561198115531367#!/compare/1539129600/1539216000

https://backpack.tf/item/3350370814

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

X = 9

Sale 4:

Sold for 9 keys

Seller: https://backpack.tf/profiles/76561198002757046#!/compare/1538784000/1538870400

Buyer: https://backpack.tf/profiles/76561198159976008#!/compare/1538697600/1539388800

https://backpack.tf/item/2946431376

X = 9

Sale 5:

Sold for 8 keys + ~0.5 keys in metal

Seller: https://backpack.tf/profiles/76561198159976008#!/compare/1539734400/1539907200

Buyer: https://backpack.tf/profiles/76561198059098316#!/compare/1539648000/1539820800

https://backpack.tf/item/2946431376

X = 8.5

Sales 6 & 7:

Sold for $15 & $12.33 on marketplace.tf

https://marketplace.tf/items/1107;5;u3003

https://manic.tf/keyprice/?at=2018-10-13 - $15 / $1.78 = 8.43 keys

https://manic.tf/keyprice/?at=2018-10-03 - $12.33 / $1.8 = 6.85 keys

X = 8.5

X = 7

Sale 8:

Sold to a quickbuyer for 8 keys

Seller: https://backpack.tf/profiles/76561198014626401#!/compare/1538265600/1538352000

Buyer: https://backpack.tf/profiles/76561198002757046#!/compare/1538265600/1538352000

https://backpack.tf/item/2946431376

X = 8

Other Sales:

https://backpack.tf/item/3392500892 (#1)

https://backpack.tf/item/3185648728 (#2)

https://backpack.tf/item/2753312534 (#3)

https://backpack.tf/item/3522810484 (#4)

https://backpack.tf/item/3149707087 - not unusual at the time

https://backpack.tf/item/6755863203 - scrap

https://backpack.tf/item/6361321268 - scammers and tf2mart stuff

https://backpack.tf/item/3587493622 - gambled/marketplace

https://backpack.tf/item/2694490855 - marketplace

https://backpack.tf/item/2693064818 - tf2mart

#1

Untraceable

https://backpack.tf/profiles/76561198085126938#!/compare/1538956800/1539129600

https://backpack.tf/profiles/76561198136053973#!/compare/1539043200/1539129600

#2

Sold with keys for Grail Broom

https://backpack.tf/profiles/76561198414067922#!/compare/1537660800/1537747200

https://backpack.tf/profiles/76561198113899098#!/compare/1537747200/1537833600

Better off being used on the Broom.

#3

Untraceable

https://backpack.tf/profiles/76561197971076263#!/compare/1537315200/1537574400

https://backpack.tf/profiles/76561198002757046#!/compare/1537228800/1537315200

#4

Sold for 9 keys?

https://backpack.tf/profiles/76561198335791307#!/compare/1539302400/1539388800

https://backpack.tf/profiles/76561198045447325#!/compare/1539302400/1539388800

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

Only 6 keys match. I don’t doubt bot.tf is correct here, but we have more reliable sales at 9 anyways, so excluding it brings no harm.

The bot.tf sale at 12 keys is completely untraceable, as the buyer didn’t have their backpack scanned. They also sold back to the bot for ~8.5 keys worth, which is again untraceable because we don’t even know who it was that bought and sold it to the bot.

https://backpack.tf/profiles/76561198305676157#!/compare/1538258400/1538344800

https://backpack.tf/item/3350370814 - more than 1 entry by the bot to show the item was “modified”

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

Sellers:

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

https://backpack.tf/item/2946431376 - 9 keys

https://backpack.tf/item/2702297665 - 9 keys

https://backpack.tf/item/3185648728 - ~11.75 keys

https://backpack.tf/item/6971615318 - 14 keys

https://backpack.tf/item/4318543409 - 16 keys

Sales at:

7

8

8.5 (2x)

9 (3x)

7 is low, excluding 7.

Will exclude 8, due to the buyer at 8, and it being the only sale at 8, one which went to a quickbuyer. https://i.imgur.com/iL5PVIr.png

Going with 8.5-9.