I worked in the car business, although I was not as big of a crook/Sales person as the ones you see today. These are trained crooks not just be experience. The one thing you can count on though is things are always changing in every field.
There is plenty of advise out there on strategies and things to do not to be taken. In fact there is some awesome advise out there. The one thing we are going emphasis here is not to get too wrapped up with the details of the deal. There are two numbers you have to worry about and you do not care how you get there.
The first is your out of the door car price, not monthly payment. That includes all the "bs" rebates, special, coupons, happy hour, black Friday and yellow Monday. Do not even listen to any of that look at the number. Make sure you factor your trade in if you are trading in your previous vehicle.
In many cases people are going to talk to you about MRSP vs invoice, bla bla bla. Does it really matter? If you are being ripped off, knowing the dealer did with the invoice vs the MRSP is not going to help you. And if you are getting a good deal, the dealer can called "MRSP", as in the most ridiculous sale price. Just look at the final number, out of the door.
The second number is your interest rate is you are financing the vehicle. Make sure you get the best deal whether it is at the dealership or at your bank or credit union. Shop around before hand so you know if the dealer is giving a better deal or not.
Here are bunch of resource that we found and they are pretty helpful. We will be adding to them as we come across more resources.
https://www.youtube.com/watch?v=06q4ekARSN4 — how to negotiate
https://clark.com/cars/eye-opening-truth-about-dealer-invoice-price/ — MRSP vs Invoice.