The only requirement for me to get 0% APR was to:

1. Have the required credit score, 760+
2. Finance the vehicle through the manufacturer's financing division
3. Finance only for the term length specified. I wanted 84 months, at 0% why not? But they would only do 60 months.
4. Had to choose from existing new vehicle on the lot. Cannot order a custom vehicle.

I did not need a down payment but I did buy a very unpopular 2012 vehicle that had been sitting for over 6 months back in October 2012. 2013 Models had already come out.