Paul - one of the major components in a tradtional "rent with an option to buy", is that you, as the buyer, will be paying an amount of money for the right to have that option. It is non-refundable. It can be paid either as an upfront deposit, or taken out of monthly rent.
The rent you pay will be an amount OVER and above what a normal rental will be. That overage will be, as Dan explained, credited toward your purchase IF you exercise your option, and buy the home.
I think a lot of consumers online mistakenly think all of the rent they pay is put towards the purchase. This is not true in a standard rent to own transaction.
There may be creative ways of structuring this, but that's between you, the seller and the attorneys who draw up the agreement.
If you do not.... or cannot .... buy the home at the end of the agree-upon term - (maybe you can't qualify for a mortgage a year from now due to higher interest rates, or poor credit) - the seller retains that upfront deposit or additonal rent.
The purchase price is set NOW...............in this uncertain market, do you really want to do that?
if there is anything questionable with your finances now.......make sure it won't be an issue down the road, or you may have paid a lot of rent for nothing.
Personally, imo, I think you're better off renting, saving your money, and then negotiating the price and terms when the time is right......you know you can move forward with the sale...and you know what the fair market value is at that time.