Unless you have great credit and a ton of cash, rent-to-own isn't for you.
The up-front costs of rent-to-own are punishing enough, much more than "key money," and the premium you'll pay in rent is staggering. Then, when it comes time to actually buy the house, you're likely to find that it's not worth what you agreed to pay for it in the first place. Or even, worse, you find that there are much better houses out there for you to buy, but you're stuck in this one.
Rent now, buy later.
All the best,