if you have those credit issues, I don' tknow of any seller/developer, who will sell based on those terms. However, if it's for some other reason, email me: firstname.lastname@example.org and I'll try to custom search for you.
The question is will this be your primary residence? The banks will allow 20-25% down on a property you will reside in but not a second home, that is more of a risk so 30% is required.
But yes, there are condos you can find that are 3 bedrooms in the 500k range. I would be glad to send you a variety of properties meeting your criteria as well as discuss financing options.
Feel free to contact me directly, I look foward to assisting you.
South Florida Brokers