If you are a veteran, there are several programs available that will qualify you to buy at 580 FICO with a 5% mortgage, possibly less if your loan in underwritten by the Texas Veterans Land Board. Additionally a veteran using a VA or a TX VLB loan can purchase a home with 0%, something few others are able to do.
If you're looking for rent to own, what you didn't mention is how much money you have available for a down payment and what you're looking to buy. You will need a minimum of 8% to 10% of the purchase price for a down payment on most rent to own properties.
If you're seeking VA financing, you just need credit that will be acceptable by VA standards and perhaps some cash for closing costs if the seller won't assist you with them.
What I have seen several times is buying a home with "lease to own" and when you pay the rent the seller stops paying the bank (that really owns the home) and you'd have to move because the home is foreclosed on.
Call me, (Frank 512-504-3474) if you need free advice on how to improve your credit.