I highly recommend you spend time studying the invoice; if the dealer is reluctant to show you the invoice, then they aren't interested in your business.
The invoice will show you how much profit they make off the msrp. Mine was about $800 if I remember, but I got it loaded. Invoice shows dealership fees, salesman commission, holdover, and ford's various "plans" for employees etc.
I told the salesman his sales fee ($250) was non-negotiable. He's got a family to feed, and the gesture won his loyalty during the negotiation. Dealership fee I initially refused to pay.
Destination charge is non-negotiable, as I understand. Advertising fee they wouldn't budge on. I refused to pay the holdover or any other fees except tax and title.
That was the offer I initialed to the floor manager, and they returned with a ridiculous counter. I added another $125 (half of dealership fee) and they made it work with extra incentives from ford (it had to be close to $2000).
Ended up paying less than MSRP out the door, including tax & title.
Check the invoice. You'll learn exactly where the money is going.