I am going to post this for the benefit of you and others. Some will apply to you, some won't.

Monthly payment is the worst way to look at a car purchase. As soon as you do that, you have given control to the dealership and will probably be taken to the cleaners.

The only number that you should be concerned with is the final, out-the-door price. Once that is firmly established, then it's time to move on to trade ins and financing.

I am the son of a career car salesman. Here's some of what he taught me.

1. Just because you can afford the car payments doesn't mean that you can afford the car. Any salesperson can give you a "low monthly payment" by stretching out the loan term to a ridiculous length and then jacking up the interest rate. This costs you money.

2. The less money you put down and the longer the loan term, the longer you will be upside-down on the loan, meaning that you owe more on the car than it is worth. (Lenders sometimes use the terms "under water" and "negative equity", which mean the same thing.) This is a very unwise financial situation to be in.

3. The dealership is a hothouse atmosphere with loads of pressure and dealerships take advantage of that at every opportunity. It's easy to get sidetracked and to lose your objectivity. Then, you wind up paying too much for a car you cannot afford.

4. As hard a pill as this is to swallow, you need to fully understand this: If you cannot put down at least 20 percent (and more if possible) and you cannot pay the loan off in 36 months, you cannot afford the car, no matter how low the payment is.
5. The salesperson is not your friend. Everything they do is designed to separate you from as much of your money as possible.
6. Dealerships will add on ridiculous items like LoJack, extended warranties, paint and fabric protection, and whatever else they can think of to pad their profits. None of these items will help the customer. Refuse to pay for them. If they won't remove them, walk away from the deal.
7. Walking away is the biggest power you have.
8. Buying a car is usually the second-biggest purchase you'll make. It's a huge financial commitment and needs to be looked at in a cold-eyed, rational way.
9. Before you ever set foot in the dealership, go to your bank or, better yet, your credit union, and see what terms they will give you. If you don't have a relationship with a credit union, this is the perfect time to start one. They may be able to beat the rates you get from the dealer.
10. You'll need to purchase full coverage insurance for the duration of the loan. Make sure you know what that costs before you buy the car.
11. Reddit is full of posts from people moaning that they want to get rid of their car for one reason or another, but they can't because they owe $17,000 on it and it's only worth $10,500. These are the same people who bought a car with little or nothing down and a loan term of 4-8 years. Don't be one of those people.
12. Don't buy any used car without paying a private mechanic or garage for a pre-purchase inspection. Ask them to look it over as if they were thinking of buying it for themselves. You'll want to find out what needs immediate attention, what will need work in the next year or so, and if the car is known for particular problems, like blown gaskets or early transmission failure. Once you know that information, proceed accordingly.