Check out how much repairs on a car would cost before buying it. You should be able to get a fair idea of what kinds of costs you will have to pay for repairs. And that's not just for when it is under warranty. What happens when you have to pay full price for an ignition coil? Different cars cost different amounts, so find out.
Find out all you can about rebates. You can either get a cash rebate, low loan interest rate or the dealer themselves gets the rebate in cash. It is the manufacturer who offers these rebates, not the dealership. This will only be available on cars available on the lot, of course.