One of my cheapest hobbies ever.
I've had many, many hobbies over the years.
I used to race in autocross/ solo 2 / slalom events - did so from mid 1980's til 2002 or so. Anyhow, set of 4 slicks? $800. In a good year you'll use up four sets. $2400 that is worthless when you're done using them. Note that that doesn't include the cost of the car, trailer, tow vehicle, engine, driveline, suspension work, gas money, entry fees, and so on.
I could buy an Etrac for about what 1/2 a season's tires cost!
What do I have to show for the untold $$$$$ that went up in smoke, racing?
Couple boxfulls of trophies. They are up in the attic somewhere.
My Vaquero was $420, and I bought a used spare coil (5.25) for $80 shipped. I think I've found around $100 worth of clad, jewelry, relics and collectible coins, total, in two years. I'll eventually recoup the investment, if I'm at it long enough, but if I were doing it as a business, well............ I'd have bailed out in the first week - a job at a mini market would be far more lucrative. I enjoy the hunt, and that's what drives me - to see what the next find is. Could be a ring, or pulltab, or..................
Anyhow, as long as you aren't out to have the latest and greatest machine, buy a solid machine and stick with it, the initial investment, is the only investment. I like the maintainance cost of 4 or 5 9volt batteries a year vs/ $800 rounds of tires - 4 times a year.. Wotta bargain MDing is!