Re-suggesting (again lol). Credit to Owe for providing the other sale.

Item 1: https://backpack.tf/item/13325581188

Sale 1: 140 keys via scrap auction.

https://scrap.tf/auctions/S6LMYX

https://backpack.tf/profiles/76561198310972287#!/compare/1694390400/1694476800

https://backpack.tf/profiles/76561198369727670#!/compare/1694390400/1694476800

Sale 2: Bulk upgrade.

https://backpack.tf/profiles/76561198872222015#!/compare/1693526400/1693612800

https://backpack.tf/profiles/76561198337378097#!/compare/1693526400/1693612800

Sale 3: Bulk upgrade.

https://backpack.tf/profiles/76561199485225128#!/compare/1693180800/1693353600

https://backpack.tf/profiles/76561198872222015#!/compare/1693353600/1693440000

Sale 4: More bulk.

https://backpack.tf/profiles/76561199393293102#!/compare/1692662400/1692835200

https://backpack.tf/profiles/76561199485225128#!/compare/1692748800/1693180800

Sale 5: Backpack sale?

https://backpack.tf/profiles/76561198040585908#!/compare/1692662400/1692835200

https://backpack.tf/profiles/76561199393293102#!/compare/1692662400/1692835200

Sale 6: Hard to tell what this is.

https://backpack.tf/profiles/76561198084161677#!/compare/1691539200/1691625600

https://backpack.tf/profiles/76561198040585908#!/compare/1691625600/1691971200

Item 2: https://backpack.tf/item/13240450298

Sale 1: Bulk

https://backpack.tf/profiles/76561198086312574#!/compare/1690156800/1690416000

https://backpack.tf/profiles/76561198334039487#!/compare/1690243200/1690848000

Marketplace sale:

https://marketplace.tf/items/tf2/31357;5;u289

Oct 6 - $399.99 / 2.02 = 198

Keys on MP:

https://marketplace.tf/items/tf2/5021;6

Sales: 140 pure, lots of bulk. $399.99/198 keys.

Taking Lemon's advice "Considering 140 took less than a day and was via auction, I'd say that is a low outlier".

Rounding and taking 200.