Are you a veteran. You can get a NO DOWN PAYMENT loan.

There are no longer any special programs for first time buyers. FHA requires 3.5% down but credit on all types has to be good.. No lates in the last year- no charge offs, etc. Minimum score 620.

You need to research your state to see if there are other programs to look into. In states with rural areas, or very depressed markets, there might be something out there.  You can also ask a realtor.  However, your low credit is a much bigger problem than not having a decent down payment.   You will probably be told to spend at least a year or 2 getting your credit in order, because bad credit = risky loan.  

WHEDA loans

VA loans, if you're a veteran

HUD loans.

Possibly.....none.

FHA programs are the most popular.  They require a down payment of 3.5% and a minimum credit score of 580.  However, banks are allowed to set their minimum credit score higher and most won't go bellow 620/640.

The Department of Agriculture has 0% Down programs.  However, you still have to meet the minimum credit score requirements and buy in a rural area.

State programs vary by state.  Some I know qualified for a state "grant" for her down-payment. However, it wasn't really a grant.  It was paid back by the bank and the bank added to her loan.  Again, there were minimum credit score requirements.