https://backpack.tf/item/7684909069

https://backpack.tf/item/7718022297

https://backpack.tf/item/7901976115

more sales here, 3 indate marketplace sales

https://marketplace.tf/items/tf2/31028;5;u15

https://backpack.tf/profiles/76561198081702842#!/compare/1586304000/1586390400 - Quicksold for 11 Keys + 27 Refined

https://backpack.tf/profiles/76561198375290326#!/compare/1586304000/1586390400 - Quicksold for 12 Keys

https://backpack.tf/profiles/76561198063841108#!/compare/1511308800/1588118400 - Sold for 15 Keys (used for another hat immediately)

https://backpack.tf/profiles/76561198111558282#!/compare/1587513600/1588032000 - The 15 Keys were used for the Jeepcap here

https://backpack.tf/profiles/76561198150072904#!/compare/1585872000/1586131200 - Bulk sale

https://backpack.tf/profiles/76561198069493147#!/compare/1586044800/1586131200 - Sold for an Orbiting Fire Horrific Headsplitter (use there)

https://backpack.tf/profiles/76561198341171690#!/compare/1588377600/1588464000 - Sold for 14 Keys

https://imgur.com/a/5cqI5jE - 5 sales at 11 Keys

https://marketplace.tf/items/tf2/31028;5;u15 - Sold for $34.99 (19 Keys), $40 (21 Keys), $34.99 (18 Keys), $18.55 (low), and $37 (19 Keys)

https://imgur.com/a/XUXqCz4 - I believe the 18 Key sale had a buyout of 17 Keys

https://imgur.com/a/EZbzbzJ - Buyers are now up to 11.2 Keys

I'm fine excluding 19 and 21 Keys, so this range will hold. Even though the sales at 12 quicksold, the sheer volume of sales supports that value as a low end.