You can find good deals but i'm not shure about condos under 20K.The lowest i see is in the mid 30K .
They list them extremey low to get to a bidding war. I have a closing for a 50K condo today. This is more realistic. Let me know if a can help.
You want to take advantage of the mortgage interest deduction. After that you will have to find renters and advertise or use an agency to find renters for you and eventually screen applicants and collet the money every month.