Having just experienced dealing with a salesman at a car dealer, I thought that some notes related to buying a car might come in handy. 
Simply stated…I would not communicate with a salesman more than I have to.  For example, never ask a salesman if he would change the offer if you agreed to buy a warrantee.  Any time I have asked a question or showed any interest in buying a certain car,  it has resulted in miscommunication and confusion.  That is why I recommend buying a car based on using a car buying service website from USAA.com  It is hooked up to their find a car service and allows you to “build a car” and then get a guaranteed price from a dealer.   This website is pretty powerful and even has graphs related to how much that car has been sold for over the past 12 months and what the average cost has been.  You don’t have to login or be a member to use their tool.

Another way to buy a car is to use Ebay.  You have lots of time to review the car being sold, and to double check what that car should cost by using sites such as USAA.com  Make sure to read all the terms of the auction to include the part about paying full payment for the car within 3 days using cashiers check.  This is listed on Ebay for each car being auctioned.  You can search Ebay closed auctions to confirm what the cars have been selling for.

 I am recommending that you can only buy a car that you have a confirmed quote in writing.  Once you change any little thing, the salesman is going to start confusing the issure and making your life miserable.