Most multiple listing services have a category for those types of listings in the search section of MLS. So to be honest any buyers agent you choose to work with can assist you with your search. Before you select an agent ask them if they are familiar with this type of transactiion & I would also recommend you get a pre approval from a mortgage lender ahead of time. Although it sounds like you are not in a financial position to buy a home yet, most sellers/ owners will want to see your financial qualifications before handing you the keys to their house with a rent option, lease purchase or land contract.
Your best bet is to rent until you can qualify to buy. Rent to own, lease purchase or rent to buy are all good deals for a seller but rarely workout for a buyer.
This is not a good choice for you as a buyer. Run from anyone who suggests that you rent to own. Buy when you qualify for a mortage do not get into a rent to own contract if you are unqualified.
The rent to own contracts are a sellers tool to get people into houses. The process is that you will sign a contract saying that you will buy the home someday in the future 12 months-18months. You will put down a sizable Non-refundable option deposit which will be applied as a downpayment when you buy when and if you buy on time. Normally an 8%-10% deposit. At the end of the contract if you don't buy the house for the original terms you will lose your deposit. Now you get to start all over again after losing $5,000 to $10,000 it's better to rent until you are ready..
Best of Luck,
Bill Carey, Broker/Realtor
Certified Short Sale Seller Specialist