People list their cars a little high because that's just what you do. For example, look
here, where it says, "If you sell your used car privately, you can expect to receive a price of $6,892. In order to get this price, we recommend you list your 2004 Toyota Prius Sedan for $7,478."
My experience:
I bought a small used sedan in 2002 from a private party. The guy wouldn't budge from a high price, and I caved. To his credit, it was in really good shape overall. However, the transmission had a slow leak, and it turned out to be an expensive repair after I put 30K miles on it. Looking back, it was a great little car, and at $4K, I didn't lose much, but I wish I had walked.
I bought a Mazda 5 on Thursday. The dealer listed the price very low (it was basically a small minivan with a manual transmission, and no one wanted it, even though it was in good condition). Given my last experience, I was very anxious during the process, so I
studied up on negotiations. I went in with guns blazing, but he knew all the tricks and wouldn't budge. For example, they say that your strongest tactic is to threaten to walk away, but he told me to leave and shop for cars at other dealerships. I didn't want to stretch the process out over weeks, so I bought it at the already excellent price after he agreed to fix the clutch. We'll see how well it holds up.
Try to find a car buying guide put out by a consumer-oriented agency. Massachusetts has
Car Smart. I made detailed notes about every step and took them with me. I had a maintenance checklist for myself, and I checked every single mechanism in that car myself. I had a list of things to look for during the test drive. I also had a checklist for the mechanic, including a request to examine any noises or other things I noticed during the test drive. I made an appointment with the mechanic and the dealer, and the dealer drove the car with me to the mechanic for the inspection. I knew about the recalls (I think CarFax tells you these, too).
To find a car:
Craigslist
carsabi.com
ebay motors (no negotiating! you can get it inspected remotely!)
cars.com
autotrader.com
For Craigslist, at least, you can save RSS searches to an RSS reader, so that you can see the ad when it first pops up. It will help you get to good deals before others do.
To price a car:
KBB (this is usually high, as in listing price, not purchase price)
Edmunds (this is usually average to low; this is based on actual sales prices)
NADA trade-in values (mark-up by $1K or so for your first bid at a dealer)
clearbook.truecar.com (my favorite; gives ranges based on market data)
For a particular car, I would make a list, like this:
$9000 KBB private-party "Good"
$8500 LIST PRICE
$8000 Edmunds "Clean"
$7800 Clearbook "Good"
$7700 NADA+$1000 Average
I put all these notes and checklists in documents on my Kindle, along with bank loan procedures (which I assume most people around here won't need) and whatever else I thought I might need. It would have been a little easier just to have them all printed out, so I could take notes on them.
I hate negotiating. I learned a lot just by standing my ground for a little while, but I find the whole concept irritating. It's a little game where you hide or lie about what you're willing to pay until the very end. There should be better ways to figure out a fair price. I'd say go the MMM route, where you negotiate with a private party over the phone based on a particular valuation which you think is fair, and then on site, you and the seller can haggle a little bit based on the actual condition, then modify that based on what the mechanic says. If you aren't comfortable with it, say "Thanks for your time, but I'm going to keep looking," and then leave. Mind games are no fun, so be straightforward. Look elsewhere, and don't think about that car again, except maybe to repeat your offer to the seller over phone or email a while later. I'm sure there are plenty of private-party sellers who would be happy for you to come to them with a fair, well-researched starting price and well-defined negotiating procedure. Calling around and discussing it over the phone will help you find those sellers faster.