As a home owner/investor I love 'rent with option to buy' because I can make unconscionable profits. And, in the end, you will not be able to buy, your saving is gone, and you are back to renting and poorer.
If you are not able to buy, don't pretend you are. This is a very slippery slop with everything working against you. Spend the next 6 to 18 months to become qualified for a home mortgage. This approach will result in you being a homeowner and save you a great big pile of money that would have gone directly into "Hip Savings & Loan' of the home owner.
Stop in at your local credit union or local bank and have them place you on a program. Perhaps you can chat with a local real estate professional and they can recommend a lender who has produced the best results for their buyers. But don't go for the 'with option' temptation.
Best of success in your home purchase efforts
ReMax Realtec Group
Palm Harbor, Fl
727. 420. 4041