There is no credit for this situation. However, if you have taxable income and you file a tax return then you may qualify for earned income credit. This is a credit for low-income taxpayers. 

Even though you're unemployed you may still have some taxable income from unemployment compensation, side jobs, investment income, etc.  Please view the information under the heading Do I Have to File a Return on pages 6-7 of the IRS link below to see the step by step instructions to determine if you should file a tax return.

I have been told that if you are homeless that you can file taxes and get at least 500.00 back. Is that true or false 

The key is that you do have to have some income.  At that point you may be eligible for some form of tax credit.  There is no credit for being homeless.

You don't get 500.  If someone else can claim you as a dependent they might get the dependent credit of $500.