Some sales in this history: https://backpack.tf/item/8357017672

34 keys 20 ref, ~34 keys:

https://backpack.tf/profiles/76561198046943416#!/compare/1613433600/1613520000

https://backpack.tf/profiles/76561198271165769#!/compare/1613433600/1613520000

Bulk for the Sunbeams Well-Rounded Rifleman (better used there):

https://backpack.tf/profiles/76561198271165769#!/compare/1614038400/1614124800

https://backpack.tf/profiles/76561198055622215#!/compare/1614038400/1614124800

40 keys + Gravelly Ghoul Calamitous Cauldron + Bubbling Lord Cockswain's Pith Helmet + Terror-Watt Respectless Rubber Glove + White Lightning Tank Top;

https://backpack.tf/profiles/76561198055622215#!/compare/1614211200/1614297600

https://backpack.tf/profiles/76561198025676501#!/compare/1614211200/1614297600

Buyout was 75 keys: https://gladiator.tf/listings/6036db100f5074fd1fb7a642

This caps taking buyers alone on the hats (40+12+9+8+14=83 keys)

75 looks like an outlier here given there's currently a seller at 50 for 18 days (https://backpack.tf/item/8385715276)

However bare in mind 34 wasn't low when the sale happened https://gladiator.tf/listings/6029f1e85ca0cfb3dc914b56 (buyers were only 29) and there are only two buyers at ~37 right now.

I'd wait for a mod response but you might need to make a range

https://backpack.tf/profiles/76561199099676397#!/compare/1620864000/1620950400

https://backpack.tf/profiles/76561198965070085#!/compare/1620691200/1620950400 - sold for 45 keys

45 - 50 will work here taking 34 and 75 as low and high outliers respectively