If you already have the car, who's name is it in now? If you can't get a loan on a car, you should save until you can buy something cash. If you put this car in his name, it's his. He can take it whenever he wants and he might not give it back to you when you are done paying for it. This is a very bad idea. Put it in your parents or a brothers name or something. Do not put it in his. I have seen this happen before, and girl I knew who did it was living with the guy and going to marry him. They broke up and he left with both cars. She took him to court, but since the car was in his name, there was nothing she could do to get it back.
At the very least, let him cosign on the car. then you can use his good credit to get the loan, but you will still be a legal owner of it.
At the very least, let him cosign on the car. then you can use his good credit to get the loan, but you will still be a legal owner of it.