I wouldn't quite my day job to do it. Not sure what the going rates are though. I'd shoot for a modest $20 - $50 to check a place out. Maybe for an extra $35 or so I'd even have my buddy Jorge mow their lawn for them.

luke. that $12 E.L.F. meter on amazon wouldn't really be good as much more than a safe distance meter. I could already tell you which parts of most houses would give you a red light with that thing. But it could be fun for convincing your friends that their TVs are haunted. :)