Will your section 8 program let you purchase? Are you able to get a loan? I'm not sure you are in a position to be able to purchase. Unless things have changed recently, Section 8 is a rental program. They are not going to put their portion of the rent towards the purchase of a property. So, you are going to have to be able to afford the entire loan, taxes and insurance etc on your own. You really should consult with a financial advisor or a mortgage lender to see if this is doable or what you need to do to make it happen.
Also, I find that most rent to own programs don't work -- be interested in hearing from others on this. To me, it means that you agree on a price today that will be the sale price in the future. If prices are going down, the buyer doesn't want to do this. If the prices are going up, the seller doesn't want to.