You could probably easily get a car loan through a car dealership that approves car loans for people with bad credit.
A credit score of 600 is not a really bad score but it's not a fantastic score either. If your score was 700 or above then you'd have a better chance of getting approved for any car loan from any car dealership.
Other ways of getting approved for a car loan with poor credit would be to have someone you know with a 700 or above credit score to help cosign the car loan agreement with you.
I'd also try to work on getting your credit score up to 700 and above and you can do that by taking out a secured credit card and paying the balance off and not missing payments.
A secured credit card can help you build you credit rating over time.