Buying stuff on Craigslist can be tricky. You have to be careful of the area you're meeting up in and make sure you get a couple of photos of the thing you're buying to make sure the seller isn't pulling the wool over your eyes.
You also have to make sure you agree on a price before meeting up, I can't count the number of times I've met up with someone and have them try to renegotiate on the spot - it's a pain in the butt.
And a good rule of thumb is that if a description of an item sounds too good to be true - it usually is. Especially when it comes to cars. I don't know much about how the darn things work aside from a few basics, and there are so many moving parts and circuits that could go wrong, I would have no idea.