Looking through Craigslist ads, you'll notice that almost all prices are listed and then there's obo. Or best offer. This is where you make you're money. Don't be afraid to talk people down. Haggle the price. Pick out flaws in the vehicle. What I usually do is check out the vehicle, then find out what's wrong if anything and offer a low price. The worst thing that can happen is, the seller will refuse. Ill give a recent example of my transaction.
I found a 1999 GMC Yukon for sale. The guy wanted $3000 for it. I take a ride to check it out. This truck is filthy. Interior is dirty, exterior is faded, and the engine bay is horrible. I notice the a/c doesn't work. The ball joints are bad. The tires are worn out. I really didn't want to but the truck after I checked it over. I told the guy that the best I can do is 1k. Seems low, yes? Well wouldn't ya know he takes it. I guess some people either need money badly or don't want to deal with repairs. So I got a smoking deal on this truck. I take it home, detail the whole truck. Replace the tires, fix the suspension, align the front end, recharge the a/c. Truck looks brand new. I put the truck back on Craigslist. I ask $3200. I get a reply the same day. The following day, the buyer wants to look at the truck. As soon as he pulls up and takes one look at the truck he wants it. I sold the truck for $3000. I make about $1200 on this deal. Took me a few days to detail the truck and repair it but it was well worth it.
As you can see, I suggested a low price and the seller let it go. More money in my pocket and everyone is happy. Sometimes you never know. Maybe the car was given to him or maybe he got it for cheap from a friend. Either way it doesn't hurt to low ball people. Don't expect it to always work though. Good luck everyone!