Sale 1:

Quicksold for 8 keys + 1 scrap to a bot

Seller: https://backpack.tf/profiles/76561198055994779#!/compare/1522972800/1523059200

Buyer: https://backpack.tf/profiles/76561198357046243#!/compare/1522972800/1523059200

X = 8

Sale 2:

Quicksold for 7 keys

Seller: https://backpack.tf/profiles/76561198062613620#!/compare/1522972800/1523059200

Buyer: https://backpack.tf/profiles/76561198055994779#!/compare/1522972800/1523059200

X = 7

Sale 3:

Sold for 6 keys + 8 ref

Seller: https://backpack.tf/profiles/76561198087456754#!/compare/1522972800/1523059200

Buyer: https://backpack.tf/profiles/76561198062613620#!/compare/1522972800/1523059200

X = 6.5

Sale 4:

Sold for some cheap cases

Seller: https://backpack.tf/profiles/76561198304815912#!/compare/1523577600/1524268800

Buyer: https://backpack.tf/profiles/76561198355843833#!/compare/1523404800/1524268800

I'm convinced that other items were involved.

Sellers:

~7.36 keys:

https://i.imgur.com/8g15Pec.png

https://backpack.tf/item/6253561015

~7.73 keys:

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

https://backpack.tf/item/6361107460

https://backpack.tf/item/6253126217

8 keys:

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

https://backpack.tf/item/6729667244

SCM: (Taking keys as $2.47)

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

$17.75 (~7.19 keys)

$18.05 (~7.31 keys)

$18.45 (~7.47 keys)

Sales at:

6.5

7

8

Given that the bot that bought it at 8 keys and 1 scrap is now re-selling for 8 keys, and there are two sellers near 7 keys, as well as the three sellers on the SCM, it should be fine to include some of the quicksales into the range. Will exclude 6.5, however. The sale without rounding is pretty close to current buyers: https://i.imgur.com/26aASJk.png

Going with 7-8.