Quoted from BobcatBowling:
I am looking to buy my very first pin. Grew up loving to play them in the arcades and now looking to add something special to my basement. Was trying to not spend a lot on a new machine, but if it makes sense I may go for a KISS Pro or Ghostbusters Pro if it makes sense.
First, welcome! It's intimidating to consider buying your first machine, but also a lot of fun.
1. For NIB, buy from a well-reviewed retailer (all of whom will ship the game to your door) and you can feel confident that you're not overpaying. Gexchange (JJ from Game Exchange here in Colorado) is a great guy and has a sterling reputation. I'm sure others will pop in with recommendations as there are a number of other great dealers on Pinside. And you can always contact a few to confirm you're getting the same price quotes (you probably will be, since Stern now sets a minimum price below which dealers cannot go).
2. If you're buying used, get a game that's 100% working since it sounds like you don't have much experience working on pins. That said, something will inevitably break or need adjustment, so be prepared to learn to do some light work (adjusting targets, screws, and switches, maybe some light soldering). Don't worry, there's a wealth of knowledge here and people will be happy to walk you through diagnostics and repair if/when you hit that point. And it's a rewarding feeling to fix something yourself! This holds true for NIB pins too, which will inevitably also have issues.
If you're going used, also consider asking around to see if a local Pinsider will ride along to check out the game with you, always nice to have help from someone that can spot issues like battery corrosion on circuit boards. They can probably also provide advice on pricing. And buy local! That way you can play the game first and have at least some sense of what you're getting, plus avoid the stress of shipping.
As far as what machine to pick, there's really no substitute for playing a bunch of different games to see what you like. Are there specific machines you loved as a kid? Might be fun to pick one of those up. That said, DMD machines are nice because they give more accessible diagnostic info when things break, plus they feel a bit more "modern" and tend to have more complex/deep rules if you're into that. But they're also more expensive. You can't go wrong starting with a cheaper title, since this will be your first pin you'll probably love it so long as it is working.