A 500 FICO score is an indication that you have credit problems. Go to your local non profit housing group. They have credit counselors. The credit counselor will go over your credit report with you and tell you what problems you have. They will also explain what you need to do to correct your credit problems.
Most lenders have a minimum credit score requirement of 620 right now. So you'd need to do some work to get your score up to that minimum required 620.
If you do not have any open, current, credit accounts that is a good start. Feel free to call or email for more details, there are some pretty detailed steps you can take to increase your score that could potentially only take you 60-90 days.
Best of luck to you!
If your score is that low, I'd encourage you to put the effort into resolving the issues that caused it to get so low. Start with a budget, pay everyone on time. Next, get a copy of your credit report and dispute any errors in writing. Finally, pay down any balances to 1/3 or below of their upper limits. This will improve your scores the fastest.
As Sally indicated, the chances of getting an approval are low, and if you did get one, your terms would not be very favorable.