Hope others will post tips on things to look out for. First I used a finance program found here before going to the dealer:
http://www.carbuyingtips.com/car3.htm
It helped me catch the finance guy in a $300 "error".
I found out CARMAX goes by Kelly Bluebook. Trade in value was $10,800 for my used car. The dealer offered $9000 till I mentioned I would go to Carmax for what my car was really worth. We then agreed on $10,500. Next I mentioned I spoke to a different Hummer dealer which offered $1500 off MSRP (they of course say that to get you on their lot). The dealer matched that offer. there were other things, but back to the finance dept: never believe the finance guy's computer display. Just because the figures are on a computer does not mean they are right. I caught him in a $300 unjustified profit margin. At least bring a calculator with you; I bought my laptop. I finally thought it was all over after the paperwork was signed. My last tip: make sure the dealer tries both sets of keys in your new ride before signing anything. My dealer said he lost the keys to my vehicle. He then (get this!) presented me with a different vehicle identical to the one I had signed for and advised me to take that one instead. On the outside it looked identical, but upon inspecting the inside I found scuff marks on the seat backs, sand on the floor. I asked for the keys and found the odometer read over 400 miles; obviously a demo. Next the dealer suddenly says he found one set of keys. I should have never taken the car off the lot without the second set of keys, but after 5 to 6 hours of waiting and negotiationg I just wanted to go home. The thought eventually dawned on me that any employee from that dealership could come over to my property and steal my car. Last night I could not sleep until I had blocked the H3 with two other vehicles to prevent towing. At work I remove a very small component from the engine; even with the key the car will not start. I also alerted the security staff at work what happened. Today I am going back to pester the dealership personally until they hand over the keys. I will perhaps use the extra set to the trade in that I forgot to give them as leverage. Thats my story. The H3 is a wonderful vehicle; this is comming from a guy who traded in a Mustang GT for it. I have no regrets, but if they had made a more cost effective, fuel efficient H2 I would have bought that instead. I like the H2 look better, but the H3 looks better to me than all the other brands out there.