Right, this.

Sale 1: Sold for 7 keys?

https://backpack.tf/profiles/76561198120672630#!/compare/1569110400/1569196800

https://backpack.tf/profiles/76561197995380138#!/compare/1568764800/1570233600

Highly likely.

Buyout was also 7 keys

https://bot.tf/stats/listings/4EE0GZRQ

Sale 2: Don't know

https://backpack.tf/profiles/76561198073176682#!/compare/1566518400/1566604800

https://backpack.tf/profiles/76561198454615761#!/compare/1566518400/1566604800

Buyout was 8 keys

https://bot.tf/stats/listings/MNLO0WNJ

Sale 3: Sold for 7 keys?

https://backpack.tf/profiles/76561198363395191#!/compare/1572134400/1572220800

https://backpack.tf/profiles/76561198065337688#!/compare/1571961600/1572220800

Buyout was also 7 keys

https://bot.tf/stats/listings/4W602N97

Sale 4: Unknown

https://backpack.tf/profiles/76561198044078011#!/compare/1571097600/1571443200

https://backpack.tf/profiles/76561198363395191#!/compare/1571356800/1571443200

Sale 5 & 6: Marketplace sales

12.35 on august 31

12.49 on september 12

https://marketplace.tf/items/tf2/1109;5;u3021

https://backpack.tf/item/3657029190

12.35/1.82 = 6.78 rounding to 7 keys

12.49/1.81 = 6.9 rounding to 7 keys

Classifieds:

https://gyazo.com/dd4c93763803790aa22ed3a8c79f01e1

Conclusion:

Marketplace sales at 7 and 7. Unconfirmed sales at 7 and 7, and possibly 8.

Taking 7 keys.