Caffeine.

https://backpack.tf/item/921601519

Sale 1) Sold for a Kill-a-Watt Chieftain's (21.5 Keys) + Cloud 9 Juju (15 Keys) + Smoking Cowl (13.5 Keys) + Memory Leak Plumber's (9.5 Keys) + 5 Keys

https://backpack.tf/profiles/76561197998934095#!/compare/1546041600/1546214400

21.5 + 15 + 13.5 + 9.5 + 5 = 64.5, which rounds to 65 Keys

Sale 2) Sold + 11 Keys + Bubbling Backbiter's Billycock for a Chiroptera Venenata Bootleg Base Metal Billycock

https://backpack.tf/profiles/76561198085880346#!/compare/1547510400/1547942400

Using this sale to update the Billycock.

Sale 3) Sold for 43 Keys

https://imgur.com/a/WUejqGh

Decided I'd include 43 Keys since another sale was the Bubble Pipe + 37 Keys for a Disco Beat Down Dapper, which has sales at 80 and 85.

Using that sale here (while bulky) would support 43 being in the range.

https://backpack.tf/profiles/76561198134266699#!/compare/1548460800/1548547200

https://backpack.tf/profiles/76561198085880346#!/compare/1548201600/1548547200