I've seen a lot of listings on Craigslist for already rented duplexes or SFHs for dirt cheap. An example is this for $39,900:
This is a fully rented 2 family. Valued at $80k. The front unit has just been freshened up and has a newer tenant in it paying $425/month. The rear unit has a longer term tenant and they pay $400/month religiously. Each unit has 2 BR's and 1 Bath. The back unit has access to the full basement, which is partially finished with extra storage. There is ample parking to the rear of property. This is virtually a turnkey investment opportunity that could make a nice monthly car payment for you without you lifting a finger.
I'm very skeptical of these deals because why wouldn't someone keep something with such good cash flow? Or at least sell it for much closer to its value? It's just a little toooo easy...