The bug bites hard and the hunt can be just as intoxicating as playing. I've been lucky. I got my first pin and grail theme, Doctor Who, for about the price you are looking, but I was an idiot. I had never lifted a playfield and I barely even knew the location of the power switch. The game has been great, but it more likely could have been a lemon.
I don't regret a thing, but if I had to do it again, I would make sure to go to have first gone to a show (like Expo or Free Play) or, depending on location, join a league or find an arcade (Replay's is down near Tampa). Maybe even see if an experienced Pinsider will let you visit and show you the ropes.
Pinside or the local league will likely get a far better machine than Craigslist or ebay if you are looking used.
Or jump in with both feet, scratch the itch and have a blast. Just make sure you have some extra cash for parts and tools.