National Treasure

https://backpack.tf/item/6518398484

Sale 1) Sold + 4 Keys + ~1 Key of Items + 40 Refined for a Mystery Smokey Sombrero

https://backpack.tf/profiles/76561198299436194#!/compare/1554768000/1558224000

https://backpack.tf/profiles/76561198016070169#!/compare/1554768000/1554854400

This would be better for the Sombrero.

Sale 2) Bulk sale for a Knifestorm Dead Cone

https://backpack.tf/profiles/76561198016070169#!/compare/1557792000/1557878400

Sale 3) Gifted

https://backpack.tf/profiles/76561198129552058#!/compare/1558828800/1558915200

https://backpack.tf/profiles/76561198203789568#!/compare/1558828800/1558915200

Sale 4) Sold for a Duped Blizzardy Storm Western Wear (12.5 Keys) + 4.66 Refined

https://backpack.tf/profiles/76561198203789568#!/compare/1558915200/1559088000

Rounds to 13 Keys

Western Mini

https://backpack.tf/suggestion/5d1a551bd381722a4b1d167e - 12.5 Keys

Sale 5) Sold + ~0.3 Keys of Items for a Kill-a-Watt Fruit Shoot (13 Keys) + 1 Key

https://backpack.tf/profiles/76561198932518745#!/compare/1559088000/1559174400

https://backpack.tf/profiles/76561198064309420#!/compare/1559088000/1559174400

13 + 1 - 0.3 = 13.7, which rounds to 14 Keys

Fruit Mini

https://backpack.tf/profiles/76561198080179568#!/compare/1557187200/1557273600 - Sold for 13 Keys + 10 Refined

Sale 6) Sold + 2 Keys + ~1 Key of Items for a Circling TF Logo Kiss King (20 Keys)

https://backpack.tf/profiles/76561198064309420#!/compare/1559174400/1559260800

20 - 2 - 1 = 17 Keys

Sale 7) ?

https://backpack.tf/profiles/76561198452491261#!/compare/1559692800/1559865600

https://backpack.tf/item/283102797

Sale 8) ?

https://backpack.tf/profiles/76561198168863803#!/compare/1556323200/1556409600

Sale 9) ?

https://backpack.tf/profiles/76561198337734785#!/compare/1559692800/1559779200

https://backpack.tf/profiles/76561198095364314#!/compare/1559433600/1559952000

https://marketplace.tf/items/tf2/382;5;u11 - Sold for $19.15 to a buy order

Calling 17 high because of a 12 day seller at 15 Keys -> https://imgur.com/a/N2Q9ksP