All credits to Mucy, who always sleepo, Blaze and Cashew.

A simple suggestion indeed

Marketplace.tf

https://marketplace.tf/items/tf2/30767;5;u7

$14.89 / $1.79 = 8.32 keys

$14.89 / $1.77 = 8.41 keys

$14.89 / $1.77 = 8.41 keys

Sale 1

Untrace

https://backpack.tf/profiles/76561198337734785#!/compare/1577232000/1577318400

https://backpack.tf/profiles/76561198975061968#!/compare/1577232000/1577318400

Sale 2

Planets HTKF? High.

https://backpack.tf/profiles/76561198069414668#!/compare/1577232000/1577318400

https://backpack.tf/profiles/76561198975061968#!/compare/1577232000/1577318400

Sale 3

Buyers price (6.25 keys roughly)

https://backpack.tf/profiles/76561198069414668#!/compare/1577232000/1577318400

https://backpack.tf/profiles/76561198337734785#!/compare/1577232000/1577318400

Sale 4

Untrace

https://backpack.tf/profiles/76561198323565601#!/compare/1570752000/1570838400

https://backpack.tf/profiles/76561198249412440#!/compare/1570665600/1570838400

Sale 5

Possibly Gambling

https://backpack.tf/profiles/76561198068388573#!/compare/1577059200/1577145600

https://backpack.tf/profiles/76561198950621219#!/compare/1577059200/1577145600

Sale 6

Gambling

https://backpack.tf/profiles/76561198068388573#!/compare/1577145600/1577232000

https://backpack.tf/profiles/76561198279539667#!/compare/1576972800/1577232000

Sale 7

Untrace

https://backpack.tf/profiles/76561198279539667#!/compare/1577232000/1577318400

https://backpack.tf/profiles/76561198341171690#!/compare/1577232000/1577318400

Additional by Blaze:

https://imgur.com/a/3RItZJu

https://backpack.tf/item/4806106589

https://backpack.tf/profiles/76561198337734785#!/compare/1579564800/1579651200

https://backpack.tf/profiles/76561198083985533#!/compare/1579564800/1579651200 - sold for 8 keys

Additional by Cashew:

https://backpack.tf/item/7425420106

https://backpack.tf/profiles/76561198311498888#!/compare/1582416000/1582502400

https://backpack.tf/profiles/76561198965851581#!/compare/1582416000/1582588800 can't tell

https://backpack.tf/item/6007202867 Can't figure out any of the sales in this history as they went pretty fast

8 - 8.5 should work here

8-8.5 it is.