Fines range... It's usually a civil ticket, which means it doesn't go on your record. Depending on the mood of the judge, it can be anywhere from $50 to $1000. If you get a cop who's having a bad day, and a judge who's getting tired of seeing trespass summons on his desk, expect a hefty fine. For story purposes, I would say he gets ticketed, summons to appear, and is fined $200 or so.
As far as the tri-field detector, while it sounds cool, I don't think would be good for a story. You don't want to blow your readers' minds with technology they don't understand. A simple EMF reader with a digital display is better because not only are they more readily available to most people (and some people even have them in their toolboxes), it's easily understood that it takes a reading, displays a number, and that's it. By trying to describe the three gauges and how they differ from one another and how to read it, I think it would be too much.
I'm also not a huge fan of the whole "incompetent ghost hunter" thing, because the vast majority of the public views paranormal research as a joke anyways. I think it could be better if you had a "Pinky & the Brain" mentality, where one person is experienced, has the tools, knows the histories, and brings a friend or someone along and that person is the one who leads his partner into trouble.
Just my two cents.