Financial questions that need an answer

I have been talking to my brother in law about buying some properties for investment in Sacramento, Ca. He found some condos in Natomas for under $100,000 which to me seems strange because if we bought it at $75,000, it would be about a $500 a month mortgage. To me this seems too good to be true if it is this cheap because who can’t afford a mortgage this little.

So what questions do I ask about these properties? What should I look for?