What to look for when buying a treadmill off Craigslist?

Swimgoddess

Please, I'd rather learn from other people's horror stories vs. experiencing my own. Aside from all the normal Craigslist scam/creeper warnings... what are things I need to check for before forking over cash? Preferred brands? As for my needs... I primarily prefer walking, at about a 4.0-6.0 incline and between 3.4-4.2 mph. I abhor running, my sprint is like 7.5-8 mph, my jog closer to 5-6 mph and I really don't EVER foresee me ever maintaining that over 45 minutes. Also prefer a brand that folds up (do most do this now? I'm so out of touch) and nothing really over $375.