Quoted from trilogybeer:Start a “wanted “ add here on pinside. In the add mention how far from your location you will travel to get one. Look specifically for one close enough to you that you can pick it up.
Be warned that wanted ads can also attract scammers.
Best bet, scour Pinside regional FS threads and the members that post in them. For your first game, buy from someone that is reputable either by local pinheads or local pinsiders, inspect in-person and pay with cash upon pickup. A small deposit via PayPal or similar is usually ok to hold a game, but again, make sure the person is reputable. Rest in cash upon pickup.
Facebook and Craigslist is also fine, but with the only caveat that you inspect in person and pay with cash upon pickup. That's really the only foolproof way of not being parted with your cash and nothing to show for it.
Most importantly, be patient. You'll find something that's of interest and in your budget if you're checking often enough. You'll have to act fast.
Good luck