Creds to Mindacos and the original suggester.

Kill-a-Watt Larrikin Robin

Sale #1

Sold for 12 keys.

https://backpack.tf/profiles/76561198011321852#!/compare/1521849600/1521936000

https://backpack.tf/profiles/76561198062791223#!/compare/1521849600/1521936000

Taking 12k

Sale #2

Sale Untraceable.

https://backpack.tf/profiles/76561198074872689#!/compare/1521504000/1521590400

https://backpack.tf/profiles/76561198011321852#!/compare/1521504000/1521590400

{Excluding}

Sale #3

Sold for a Massed Flies Rebel Rouser along with 2 keys. {Better for Rouser}

https://backpack.tf/profiles/76561198083134207#!/compare/1521158400/1521244800

https://backpack.tf/profiles/76561198396317195#!/compare/1519689600/1521244800

{Excluding}

Sale #4

Sale Untraceable.

https://backpack.tf/profiles/76561198396317195#!/compare/1504483200/1515888000

https://backpack.tf/profiles/76561198327078449#!/compare/1515715200/1515801600

{Excluding}

Sale #5

Sold for 11 keys.

https://backpack.tf/profiles/76561197964171516#!/compare/1515369600/1515456000

Taking 11k

Sale #6

Sold for 10 keys along with 13 refined.

https://backpack.tf/profiles/76561198112821447#!/compare/1520640000/1520726400

https://backpack.tf/profiles/76561198037155834#!/compare/1520467200/1520726400

Taking 10k

Sale #6

Sold for ~9.5 Keys.

https://backpack.tf/profiles/76561198112821447#!/compare/1522972800/1523059200

Taking 10k

Sale #7

Sold for 10 Keys.

https://backpack.tf/profiles/76561198196211083#!/compare/1524182400/1524268800

Taking 10k

Using Mindacos' range suggested in the comments of the previous suggestion.

https://backpack.tf/suggestion/5ab7969acf6c7508c65fdae9

Final Price: 10k-11k