Quoted from goldenboy232:
True, although sometimes those are the good deals because it's some family that has a game, has no idea how to fix it, the "problem" is a shorted light socket or something, and they'll unload it at a discount. You get it home, find/fix the short, and then start the refurb. I also like these cases because often they don't even know how to remove the glass and lift the playfield. That tells me they haven't messed with it and broken anything most likely.
This is a good point. People who don't really know what they are doing usually make things worse trying to "fix" things. I did get one machine for $150, a Bally Monte Carlo (with almost perfect backglass and an OK playfield). It is a somewhat decent machine to play although not particularly popular. It needed some work to get it going, which I understood when I bought it, and that was OK because I wanted to learn how to work on one. But what I found out is that someone in the past (not the person I bought it from) had attempted plenty of repairs, and each one was a mess that required more work from me than if they had just left it alone. Switches bent at all sorts of horrible angles, pieces broken off, hacks installed, etc. Everything worked out OK because I managed to get it all fixed, but I agree, it is better is has been left untouched by someone who doesn't know what they are doing. When I have had to fix things on unhacked machines, I found that once you figure out where the problem is, most of the time it just takes a very small and well-applied switch adjustment, or a bit of cleaning, or maybe some soldering on a broken wire, and you are good to go. Simple stuff, but you need to be able to understand how to find where the problem is and how it should be properly fixed.
To the OP, you will find I think that you can get a pretty nice EM for $500-800 if you are patient and keep looking. Any maybe less, like I said, I got one for $150. This is assuming you don't mind working on one, which you said you wanted to do. The best ones are with a good backglass and a decent playfield, but maybe needing some mechanical work. When you first start out, you can get lots of advice here on how to start fixing it so you don't make things worse yourself when you start working on it.
If you want to get one to work on so you can start learning how to fix them, I would recommend a single player if possible (agree with 1974DQ). 4-player has so many more score reels to deal with along with additional stepper units that a single doesn't have, it will be more intimidating to start out with.
Good luck, I was just like you less than a year ago. It will be very enjoyable. Keep looking, keep asking, and I'll bet you'll get a good one. Then remember, these things have an amazing ability to replicate themselves. I got my first one and I thought it would be all I would need to keep me busy for a long time. Well, it turned into 3 pretty quickly, and I'm not even sure how that happened.