I'll second what matchewed said. If I were going to buy a $150K house, I'd want to get $15,000 profit out of it, after vacancy, taxes, insurance, and repairs/deferred maintenance. Otherwise you might as well just put it in the stock market long term. You can look up taxes, and call an insurance company for insurance (rental insurance is more than your primary residence). For maintenance I assume I'll need to replace the roof and HVAC every 15 years, plus smaller miscellaneous stuff. Most properties on the market do not get me that 10% ROI. I usually spend months looking for the right deal.
I've never been able to make the math work for a mortgage on a rental, but YMMV depending on local conditions.