I just go in, talk numbers and let them do the rest. Do your research beforehand to see if you have a bank or credit union that has good rates for auto loans, if financing through dealership can’t beat those rates, go through your bank or credit union.
They will always ask what you’re thinking about paying in terms of a monthly payment. They do this so they can dick around with the numbers and inflate prices to get into that price range you just gave them.
I always get pre-approved for an amount equal to the MSRP of the vechicle I’m interested in, plus taxes, less any down payment. I do this for multiple banks first before even looking at a vehicle at a dealer. This lets me know what my payments are going to be and also saves me time (and frustration at the dealership.
It also saves me money. Having a pre-approval tells the dealership what you are spending and that you are ready to spend the money. Now it frees you up to deal on the price of the vehicle - you leave no room on the table for them to inflate the price through financing tactics. You are dealing directly based on the price of the vehicle.
If the asking price is above MSRP, you should be asking why. If you want lower than MSRP, you’ll need to have some very good reasons and negotiation skills.
Doesn’t that sound awesome? Go and secure your financing on your own time, in a stress free environment, not going back and forth with a pushy salesman with obscure monthly payment numbers?
Then you walk into a dealer with your pocket full of that pseudo-money (i.e. pre-approval) and you say, “I see that 2020 Sport Touring over there and I’m interested in buying it today. I see you’re asking $25 for it. I’m pre-approved for $21 and I have $3 to put down. Sound like a deal?”
And if you’re ever trying to decide whether to pay cash or get a loan, you need to check current interest rates. Right now interest rates are so low you are dumb to pay cash for anything. For example, you get an interest rate of 3% for the car loan, then you take the money you would have paid cash for the vehicle and now you put that lump sum into an investment account and make 5%. You just MADE 2% because they loaned you the money.