Hey there Matthias,
Since I'm kinda the Lease-to-Own guy here on Trulia, maybe I can help you.
To be able to find/move into a lease-to-own house, you'll need at least 3-5% upfront. If you decide to purchase the house, the 3-5% (or whatever the seller will need from you) will be credited towards the purchase price when you buy BUT if you decide NOT to buy the house, the 3-5% us non-refundable. I may be able to even offer you Rent Credits.
If your serious about finding a house and have AT LEAST 3-5% upfront (I DO NOT WORK WITH TIREKICKERS), shoot me an email with what considerations you have for your new house (ie...3 bed, 2bath, no garage, etc and what you can comfortably afford for a monthly lease payment & purchase price) and i'll start looking to acquire a house for you.
Lease-to-Own Professional and Independent Consultant