How To Bargain And How Much To Bargain When Buying A Used Car?

First, you will probably never know what a car lot owns their car for. The best place to start is with http://www.kbb.com. Book a car with ALL options (you can back the options that you will not be getting out later). Book at dealer trade-in value, private party value, and dealer retail. You will now have a starting place for vehicle cost.
All car lots take their vehicles in for some amount in relation to wholesale KBB less reconditioning, market value, and overall condition with the idea that the vehicle will be placed on the lot for retail at wholesale less market value (what is currently happening in the local market) and condition. Condition can be a plus or minus dollar amount. Pristine vehicles get top dollar on trade, not so nice vehicles that can be retailed but are not up to par receive less as a trade in, and usually are priced less for retail.
Having said all that what does it do for you? Well, with Book values in hand you will have an idea of how much profit a dealer may have in the vehicle. If it has a wholesale book of $20k and is priced at $25k there is probably close to $5k profit sitting there.
Now what? Use the wholesale book as your starting point and add some profit to it, make an offer and see what happens. You might offer somewhere between $300. and $1500.00 over wholesale, your call. Whatever you offer be prepared to say no to a counteroffer or enter into negotiations.
Most all vehicles are worth what the lot price is and the dealer is entitled to the profit, and if one paid that it’s OK! However, we are trained and have learned to negotiate (actually the dealers created the negotiations more than 50 years ago) so we are always looking to get a lower price.
bestofbuying to you, Chuck Norlin
http://www.thebestdealofyourlife.com

Why bargain?
Why waste time and money with a double-talking car dealer when you can buy your dream car from government seized auto online auction, where you can buy a car 90% off Retail Value?
This may help you:http://economy-car.info
Good luck!

Be well prepared – print out ads for other similar cars and bring them with you to look at the others.
Act stupid – pull out the wrong ad (for a lower amount) and ask why there is a price difference from the ad. Then apologize when the seller points out your mistake.
Research – use Kelly Blue Book to see what options are worth. Punch in the figures for cars you find and then change the options on the cars to see what the value of the used car changes. Include changing the mileage to see how much of an impact that has.
Search archives – see if the car has been for sale for a while. If you can search the archives of a local paper (assuming you found an ad in the paper), see if it has been for sale.
Compare – make a quick count of how many cars of that type are for sale. Compare that with how many of a similar car form another maker are available. If there are a lot of your car on the market, you can bargain more.

There isnt much to say, the first 2 answers give almost all you need, except I suggest you to use http://www.edmunds.com instead for research, it has a used car calculator thats much more accurate than kelly blue book (kbb), KBBs are often overpriced.
The edmunds website also offers lots of advice on buying a used car (dont worry its all free), check it out.
I suggest you to read all articles, they really help, and it gives you some strategies and tips that’ll come in handy when you negotiate
Goodluck

First anwer is very good. If I could add another point, it would be
Inspect – Have it checked thoroughly by a mechanic you trust. Have him document all items in need of repair along with the cost to repair.
Use this price when bargaining.
Example: “It will cost me $600 to replace these worn tires. Either replace the tires or take $600 off the price you are asking.”