Blitzkrieg Bop

https://backpack.tf/item/6446291603

Sale 1) Bulk sale for a Sunbeams Tundra Top + Sunbeams Burning Question

https://backpack.tf/profiles/76561198033038646#!/compare/1561334400/1561593600

https://backpack.tf/item/4491971365

Sale 2) Bulk sale for 110 Keys

https://backpack.tf/profiles/76561198198869057#!/compare/1558310400/1558828800

Sale 3) Sold for 20 Keys

https://backpack.tf/profiles/76561198093707809#!/compare/1560470400/1560556800

Low outlier.

Sale 4) Sold for 22 Keys

https://backpack.tf/profiles/76561198809836021#!/compare/1561075200/1561161600

https://backpack.tf/profiles/76561198099132915#!/compare/1560988800/1561161600

https://backpack.tf/profiles/76561198267189538#!/compare/1561075200/1561161600 - 13 of the Keys were used for the Pillar

https://backpack.tf/item/4431906352

Sale 5) Sold for 25 Keys

https://backpack.tf/profiles/76561198076020691#!/compare/1563494400/1563580800

https://backpack.tf/profiles/76561198104816709#!/compare/1563494400/1563580800

https://backpack.tf/profiles/76561198069388365#!/compare/1563494400/1563580800 - The Keys came from here first in the Dragonborn trade.

Sale 6) Bulk sale for a Stormy 13th Hour Ye Olde Baker Boy

https://backpack.tf/profiles/76561198104816709#!/compare/1564790400/1565308800

https://marketplace.tf/items/tf2/15148;15;u702;w3;pk81 - Sold for $45.99 when Keys were ~$1.80 each

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

45.99 / 1.80 = 25.55, which rounds to 26 Keys

https://imgur.com/a/FYbgMc7 - Buyers at 20 Keys

https://backpack.tf/u/76561198048851745

https://backpack.tf/u/76561198026129220