I've used a similar version of Chuck's method before on buying a used car. Here, timing is everything, and to some degree, so is how popular the car is you are wanting to purchase.
Two years ago I needed a car to replace the green Dodge Intrepid that I totalled after hitting a deer (on the way home from the THSCC Christmas party). Shawn and Brenda gave us a ride home that night (Thanks again Shawn). Anyway.. I actually wanted a 97 Intrepid, the last of the old big body style (call me stupid). At that time, the new body styles were much more popular. I found the car at a Leith lot and went shopping on Dec 26. It was about 20 degrees and very windy. Eventually a salesman came out. I'm sure they debated over who was going to go out in the cold and dark to see the only customer on the lot. I wasn't even going to ask the guy about the specific car I was looking for. I would much have preferred to "stumble" over it. Well, I couldn't find it, so I had to ask him where it was located.
Funny thing was.... we looked everywhere and he couldn't find it either. So, into the dealership we went and I asked him "Can't you look it up on the computer and find out where this car is?" (no he couldn't) Long story short.... supposedly a salesman had taken it home and they didn't know when it would be back. Okay... I asked... when salesman and what's his number? Now he actually does look it up on the computer and says it's on another lot. Well, "Which one?" I asked. Eventually he told me and I said "Thanks, I'll go look at it." The salesman, sensing that I was interested in the car (which was obvious) wanted to start talking numbers. I told him politely that there was no way I could do that until I had seen the car. I wanted to slap him for even asking that at this point. Ironically, he wanted to go with me to the other dealership. He must have just wanted to protect his commision and there certainly weren't any other customers on the lot that night.
Anyway, we went to the other dealership.. another Leith dealership of course. We got there and they couldn't find the car either. At this point, I was both laughing at the hilarity of this, and their seeming inability to find their own cars, and a bit angry that I might have now spent two hours just trying to find a silly car that might be a piece of junk, which they might not have. After being told everything from "the car has been sold" to "it's not here" to a few other things... I finally asked for the specifics enough times and some guy actually insisted that the car was on the lot. But where? was the question nobody could answer.
It wasn't on the lot in the rows of cars for sale. It was stuck behind a fence, in the dark, waaay away from the shiny newer ones. They were either ashamed to put this thing on the lot with the rest of the cars, or were trying not to sell it for some reason.
Anyhow, the car was immaculate with only 30,000 miles. Not bad for a 5 year old car. The Carfax rept checked out fine and even the city where the car was inspected was consistent with the "story" I got on the previous owner from the dealer.... which I never believe anyway.
But.. I wrote a figure down on my business card, and told the guy to call me if he could sell it for that. I made it clear that this was not the price for the car- it was the value of the check I would write for the car- including tax, license, tags, dealer this or that, paper floormats, or whatever else he wanted to call it. He needed to write down that figure in the "grand total" column and work backwards from that. I didn't care if he charged me $1000 for the car and called the rest "dealer prep." That figure was all there was.
I told him I understood if he didn't want to sell it for that but to call me if he changed his mind. It was about $2400 off the asking price and just a little above NADA wholesale for an "average" car. I truly didn't figure I'd hear from this guy for at least a day or two if at all. At 9:05 the next morning (I think he got in at 9:00) , he called me. That was funny because his first words were... "well, I think it's time for a counter-offer". I laughed, and after he called me again, and maybe even a third time, we worked it out. I think I might have caved in $200, which got me to the price I was really willing to pay anyway. I wondered when it was all over if I had offered him too much! But it was a fair price to me and a price I felt good about. I don't expect something for nothing, but to get a nice car for a price I like to pay from a dealer is not something I expected to happen.
After we agreed on the price, I was waiting for something else to go wrong. But honestly, it didn't. I took a certified check for a few hundred less than our agreed up on price, and the rest in cash. That gave me last minute negotiating room for any "surprises." But from there, it all went fine and the car has been fantastic, even for a Dodge.
So.. if you are still reading.. a few tips:
1) Write down the amount your check will be on the back of the business card you give the salesman- and BE CLEAR that this is the GRAND TOTAL for everything, not just the price of the car. Tell him you'll give him a certified bank check, even if they don't require it.
2) Truly be willing to walk away.
3) Leave yourself a tiny margin to negotiate. I left myself about $200 on a roughly $6000 car (that they were asking about $8500 for). A salesman needs to have something to brag about and something to get a sense of victory over. Let him have the seeds for a great fish story.
4) Pick a time when sales are slow and needed. The last week of the month, the quarter, or even better, the year.
5) Cold winter nights after Christmas might be a good time

.
6) Out of the way dealerships might be a better place than those on the beaten path to shop.
7) If you pick a really popular car, in a popular color, that everybody else wants and they are hard to find.... this aint' going to work so well.

Be sure to run a Carfax report. Buyer beware and all the usual caveats apply. Don't believe anything a salesman says about the history of the car. Take it at face value.
9) Your offer should be a cash offer. If you can't pay cash, get the money from somewhere else. Don't even think of financing it from the dealer.
If you find a special, one of a kind car, located five states away, you have to use a somewhat different method.....
Good luck in your shopping ventures... and as always, YMMV.
Miles