These programs exist, but they are limited and can be risky. A seller willing to do this has to have terms that are favorable to them if you don't complete the transaction. The other factor with Lease options is that you are typically securing the final price today, in an appreciating market this is good for the buyer, but most markets are depreciating. You may lock in a higher price than you should be paying when you convert to purchase.
My suggestion is to save up some money, work on your credit and get prepared for a purchase when you have everything else lined up.