Now if you charge the car, the vendor will pay a discount fee, which he will likely include in the price of the car. So, you may not know it, but either way, you pay the same. Dealers have profit margin requirements just like any other business.
If you’re a good negotiator, then you’ll get the best deal. BTW, a take-it-or-leave-it attitude generally won’t get you a better deal. Be prepared to spend a couple of hours negotiating. Think of it as a game for entertainment purposes.