You know that old saw, "If a deal looks too good to be true, it is." The reality of that has been bugging the heck out of me the last few weeks. There are other dealers in the region who advertise some AMAZING deals on new cars. They're running ads showing prices thousands of dollars less than any other dealership. They're doing everything they can to get you onto their lot - they know that if they can just get you in the door, the odds of them selling a car go up exponentially. So, they promise the sun and moon and the stars and the kitchen sink and a new toaster. (Ok, that last part wasn't true, no one has offered a new toaster for years and years.) all to get you to visit them.
There's a technique called "Rebate Stacking," you can read about it here, that seems to be one of their favorites. In addition, they'll include semi hidden conditions. They'll require you to finance through them, (then they can mark up your credit rate), or they may insist that you trade in a car with a minimum value, then they'll low-ball you on the car to make up the difference.
There is a great article on www.thetruthaboutcars.com that talks about this and other deceptive tricks. The author has a suggesting for how to suss out a phony deal. He suggests that you offer to put a deposit down on that specific car and at that price. If the dealership won't take your deposit, and insists you come in and talk first, it's very likely the the deal, or vehicle are not going to be available.
(Side note, please, if you do nothing else - try and determine the ball park value of your car before you trade it in. Remember, you're looking for an approximate wholesale value. Take a little time and visit the websites for Kelly Blue Book, or even better find Edmunds.com's True Market Value. And for heavens sake, please be realistic about your car's condition.)
Anyway - dealerships all pay the same amount for new cars. Think about it, if we don't have the color or model you like, we'll try to swap with another dealership. We give them one of our cars, and they ship us theirs. Would dealerships really do that if one of them was paying a lot less for their inventory?
I'd also recommend you read Yelp and Google reviews of the dealerships you're considering working with - see what other people's experiences have been like. Sure, everyone has a bad day every now and again, but if you see the same complaint over and over again . . .
So, last thought, please don't feed the trolls. If less than reputable dealerships are successful at getting you in by using manipulative or shady advertising techniques, they're going to keep doing it.