Bingo is fun.

https://backpack.tf/item/5236194036

Sale 1) Sold to a quickbuyer for 30 Keys + 12 Refined

https://backpack.tf/profiles/76561198098770777#!/compare/1530748800/1537747200

Sale 2) Sold for 42 Keys

https://backpack.tf/profiles/76561198080179568#!/compare/1538784000/1538870400

The IDs match.

Sale 3) Sold for 24 Keys?

https://backpack.tf/profiles/76561198180769950#!/compare/1539216000/1539475200

Low.

Sale 4) Sold for a Death at Dusk Doctor's Sack (27.5 Keys) + Miami Nights Engineer's Cap (16.5 Keys)

https://backpack.tf/profiles/76561198317606171#!/compare/1539475200/1539561600

27.5 + 16.5 = 44 Keys

Engineer's Cap Mini

https://backpack.tf/suggestion/5bd54539cf6c7565f9790c3f - 16.5 Keys

Sale 5) Sold for a Starstorm Insomnia Gauzed Gaze

https://backpack.tf/profiles/76561198299238885#!/compare/1540425600/1540512000

This is being used for the Gauzed.

Sale 6) ?

https://backpack.tf/profiles/76561198025618418#!/compare/1540339200/1540425600

https://backpack.tf/profiles/76561198397457031#!/compare/1533513600/1540598400

https://backpack.tf/item/5191831766

Sale 7) Sold + ~21 Keys of Australiums + Fountain of Delight Bucking Bronco for an Eldritch Flame Prehistoric Pullover

https://backpack.tf/profiles/76561198080714435#!/compare/1533427200/1533513600

This would probably be better used to update the Prehistoric.

Sale 8) ?

https://backpack.tf/profiles/76561198117433241#!/compare/1533340800/1533427200

https://backpack.tf/profiles/76561198024867201#!/compare/1533340800/1533427200

Sale 9) Sold for a Blizzardy Pith Helmet (12.5 Keys) + Stormy Storm Capo's (no Mini) + Circling TF Logo Carouser's (12 Keys) + Orbiting Fire Beret (11 Keys)

https://backpack.tf/profiles/76561198024867201#!/compare/1534464000/1534550400

This sale is 35.5 Keys + the Capo, which will likely make the sale around 48 Keys.

Pith Mini

https://backpack.tf/suggestion/5bd8850ecf6c751a6e185873 - 12.5 Keys

Beret Mini

https://backpack.tf/suggestion/5bd88d26cf6c75262445310e - 11 Keys

Sale 10) ?

https://backpack.tf/profiles/76561198231567688#!/compare/1536192000/1539302400

Sale 11) Sold for a Well Worn Hot Blue Mew Scattergun

https://backpack.tf/profiles/76561198316071886#!/compare/1538092800/1538265600

https://backpack.tf/profiles/76561198313769156#!/compare/1538092800/1538438400

High outlier.

https://marketplace.tf/items/30119;5;u107 - Sold for $75 when Keys were ~$1.83 each

75 / 1.83 = 40.98, which rounds to 41 Keys

https://imgur.com/a/LwW01cw - Seller at 36 Keys

https://backpack.tf/item/5220889717