https://i.imgur.com/FJMOd8l.png - Sale 2 was a bulk sale

Sale 3 can be used if you find sales for the spelled version of the Kabuto that are consistently higher than the non-spelled version. If the sales are equivalent to those for the non-spelled version, treat them equally. In this case, the spelled sales are:

https://backpack.tf/profiles/76561198079821428#!/compare/1697760000/1698278400 - 55 Keys

https://backpack.tf/profiles/76561198261483133#!/compare/1699142400/1699228800 - Tesla Coil Voodoo Juju + 3 Keys (no other traceable sales)

https://backpack.tf/profiles/76561198013925436#!/compare/1701129600/1701216000 - Spelled Miami Nights Pillar + 15 Keys

The Pillar sale shouldn't be used because I genuinely don't know what to think about its other two sales

https://backpack.tf/profiles/76561198065903789#!/compare/1699660800/1699833600 - Paid 110 Keys

https://backpack.tf/profiles/76561198013925436#!/compare/1699660800/1699920000 - Added 16 Keys for a ROFP Orb. Fire Brain Bucket

That'll make the third sale 56 Keys here. That should be your low end.