Why they go to down payment first
Asking about your down payment early finds the cash you have and steers the talk toward a monthly payment.
Early in many dealership conversations, someone asks how much you're planning to put down. It sounds like a simple logistics question. It's also one of the most useful things a dealer can learn about you.
Your down payment is cash you actually have. Knowing it tells the dealer how much room there is, and once it's on the table, the talk tends to slide toward a monthly payment: with this much down, the payment would be this much. From there, price, trade and term can all get folded into one figure.
A down payment is genuinely good for you. It lowers the amount you borrow, the interest you pay and the chance of owing more than the car is worth. At 7% for 60 months, every $3,000 you put down lowers the payment by about $59 a month. But it doesn't change the price of the car by a dollar. Price is price, whatever you put down.
So decide your down payment at home, from your own budget, and lock the square to that number. At the dealership, it just isn't the first topic. If someone asks, you can say you'll decide how much to put down once the out-the-door price is settled.
If you're asked for a bigger down payment to make the numbers work, take that as a sign the price or the payment is the problem, not your cash.