Countering because I don't believe Asz intends to resuggest.

https://backpack.tf/item/6742446657

Sale 1) Sold for 10 Keys

https://backpack.tf/profiles/76561198114552735#!/compare/1559088000/1559347200

Sale 2) Sold for a Green Confetti Airdog + 1 Key + small Items

https://backpack.tf/profiles/76561198114552735#!/compare/1559433600/1560988800

Fits in the range.

Airdog Mini

https://marketplace.tf/items/tf2/30767;5;u6 - Sales at 11 and 12 Keys

https://imgur.com/a/HhicGuN - 6 Day Seller at 10 Keys

https://backpack.tf/item/6674137275

https://backpack.tf/item/7575938254

Sale 3) ?

https://backpack.tf/profiles/76561198107067824#!/compare/1560124800/1561334400

https://backpack.tf/profiles/76561198055860134#!/compare/1560816000/1562025600

https://backpack.tf/item/6962486657

Sale 4) SCM sale

https://backpack.tf/profiles/76561198810590651#!/compare/1559088000/1559174400

https://backpack.tf/profiles/76561198326056285#!/compare/1555804800/1561075200

https://backpack.tf/item/6756467346

Sale 5) Sold for 9 Keys + 17 Refined

https://backpack.tf/profiles/76561198818878316#!/compare/1560211200/1560556800

https://imgur.com/a/bvZ2qDT - When I first commented on Asz's suggestion, Buyers were up to 9 Keys + 32 Refined, so I'm calling this sale low.

Sale 6) ?

https://backpack.tf/profiles/76561198341171690#!/compare/1563148800/1563235200

https://backpack.tf/profiles/76561198450901431#!/compare/1563148800/1563235200

Sale 7) Sold for 10 Keys

https://backpack.tf/profiles/76561198450901431#!/compare/1563494400/1563667200

Sale 8) ?

https://backpack.tf/profiles/76561198080179568#!/compare/1563753600/1563840000

https://backpack.tf/profiles/76561198306787854#!/compare/1563753600/1563840000

Sale 9) ?

https://backpack.tf/profiles/76561198048139829#!/compare/1564358400/1564444800

https://backpack.tf/profiles/76561198357548086#!/compare/1564444800/1564617600

Sale 10) Bulk sale for an Eldritch Flame Prehistoric Pullover

https://backpack.tf/profiles/76561198357548086#!/compare/1564963200/1565049600

https://backpack.tf/item/6885929329

Sale 11) Sold for 11 Keys

https://backpack.tf/profiles/76561198403833291#!/compare/1562284800/1562457600

Excluding the low $17/$16.50/$15.01 sales, the Marketplace sales convert to 12 Keys ($22.22), 13 ($23.99), 14 ($25.99), and 11 Keys ($19.99).

https://marketplace.tf/items/tf2/30977;5;u60

https://imgur.com/a/R2g6Gym - Current Sellers at 11 Keys, 13 Keys, 13 Keys, and 15 Keys. Buyer at 8 Keys

https://backpack.tf/item/6885929329

https://backpack.tf/item/6756467346

https://backpack.tf/item/6926749270

https://backpack.tf/item/7676829107

https://backpack.tf/u/76561198341171690

Since one of the Sellers at 13 Keys hasn't sold for a Month, I'm calling 13 and 14 high.