You might consider looking at mobile or manufactured homes. Example: A $20,000 mortgage at 7% for 7 years would cost you $302 a month. Understand that that doesn't include property taxes or other expenses . . . . just the principle and interest. And you wouldn't be able to find a conventional mortgage. For that amount, it very likely would have to be owner financing.
Still, find a mobile home or manufactured home being sold by the owner (many/most ARE sold that way) for under $20,000 or so. Then negotiate the terms and conditions to keep your payments where they need to be.
Hope that helps.
Lynn911 Dallas Realtor & Consultant, Loan Officer, Credit Repair Advisor
The Michael Group - Dallas Business Journal Top Ranked Realtors