Sale #1

https://backpack.tf/item/15649218780

?

https://backpack.tf/profiles/76561199768678150#!/compare/1773100800/1773705600

Sale #2

https://backpack.tf/item/15445519059

?

https://backpack.tf/profiles/76561199209261544#!/compare/1776470400/1776556800

Sale #3

https://backpack.tf/item/15445519059

6 keys 24.33 ref

https://backpack.tf/profiles/76561198141187659#!/compare/1777075200/1777248000 (ID: 16969232070)

https://backpack.tf/profiles/76561199232380670#!/compare/1777161600/1777248000

Rounding to 6.5

Sale #4 (credit to BC)

"Bought on steam market for $24.75 AUD

Mann Co. Supply Crate Key = $3.40 AUD

24.75/3.40 = 7.27941176471

= ~7.5 keys

Steam community market history: https://imgur.com/a/uYB5mZ3

Cost of Mann Co. Supply Crate Key: https://imgur.com/a/WJbyRMW"

Current sellers:

$19.99 on mp.tf

$18.09 on SCM

8 keys on bp.tf (2x)

Sales: 6.5, 7.5

Final price: 6.5 - 7.5