Resuggesting with lemon's proof.

https://backpack.tf/profiles/76561198039117789#!/compare/1603324800/1603411200

https://backpack.tf/profiles/76561198047941585#!/compare/1603238400/1603324800

pure sale of 110 keys

https://backpack.tf/profiles/76561198133684216#!/compare/1598400000/1598486400

https://backpack.tf/profiles/76561198047941585#!/compare/1598400000/1598486400

Cloudy moon soldiers stash for a tf logo luchadore, morning glory ballcap, scorching fro, and the poisoned shadows fatman's.

-reference, too old-

https://marketplace.tf/items/tf2/30911;5;u76

Thanks to lemon for finding the proof below:

https://backpack.tf/profiles/76561198103054597#!/compare/1596672000/1597017600

https://backpack.tf/profiles/76561198133684216#!/compare/1596758400/1597017600 - Another sale for a Burning Flames Sergeant's Drill Hat (136 keys)

Can't find a buyout

Mini for Drill:

https://backpack.tf/profiles/76561198084126218#!/compare/1597708800/1597795200

https://backpack.tf/profiles/76561198077899354#!/compare/1597536000/1600041600

https://backpack.tf/item/149314895 https://marketplace.tf/items/tf2/183;5;u13 - Looks like $250 / $1.84 = 136 keys

Buyout was 155 keys https://bot.tf/stats/listings/4ZP2JK0Q

https://backpack.tf/profiles/76561198084126218#!/compare/1597190400/1597276800

https://backpack.tf/profiles/76561198103054597#!/compare/1597190400/1597276800 - Bulk, Arcana Black Watch

https://backpack.tf/profiles/76561198013840333#!/compare/1596585600/1598400000

https://backpack.tf/profiles/76561198133684216#!/compare/1596153600/1596585600 - Low, Added a Lot for a BF Cowl.