For a robo hat this one isn't too bad.

Sold with a Strange Festive Jarate(~1 Key) for an Australium Spec KS Knife(~21 Keys with Overpay at the time)(~20 Keys total)

http://backpack.tf/profiles/76561198099022779?time=1431154800 -> http://backpack.tf/profiles/76561198099022779?time=1431241200

Sold for a Miami Nights Das Maddendoktor(22 Keys with Overpay)

http://backpack.tf/profiles/76561198139697647?time=1431068400 -> http://backpack.tf/profiles/76561198139697647?time=1431154800

Sold for a Smoking Brown Bomber(19 Keys with Overpay)

http://backpack.tf/profiles/76561198089267125?time=1430290800 -> http://backpack.tf/profiles/76561198089267125?time=1430463600

Sales seem to fit, 19-22 Keys should be fine.

Additional Proof/Counter-Proof/Constructive Criticism/Feedback is always appreciated.