You're clearly getting a lot of answers from people that have never worked at a car dealership.
If your score is 500, not a chance, don't bother trying.
At 600, not likely, but maybe.
Frankly, if you know your credit is bad, it's probably worse than you think it is. If you just had a repo or foreclosure or know you've got things currently in collections you're probably in the mid 400's.
If it's just $5,000 in debt that your worried about, it's not a big deal at all. As long as you're current you very well might have a great credit score. But, with only $1,100 a month in take home they will tell you your debt to income ratio is out of line and you won't qualify.
By the by, with good credit, the loan you're looking at would be about $200 - $250 a month. Probably out of reach to have a car payment that's 25% of your before tax income.
The one answer was partially correct, the dealer's all WANT you to buy a car. It's the bank that won't lend the money to someone that has a track record of not paying the money back once they get it.
With a credit score of 600, there's no way you'd qualify for a 12% loan. you'd be looking at a lot closer to 20%, maybe even high 20's. The legal max is now 29.99%.
If you've got 600, your debt to income is what's going to kill the deal. No real harm in trying though. Go ahead and get out to a dealer, don't go with high hopes though. I think your chances are less than 1,000 ; 1 to get the loan.