Why are cheap properties selling for millions?

[James Guillot]

In my location, I've noticed that when I'm trying to run comps off public MLS sites like Zillow and Redfin, there are properties marked as sold for over a million dollars. These properties are never worth more than 60-90k. Is it some sort of error or maybe something to do with investors evading taxes? I guess I could understand if it were 1 or 2 if those properties had some sort of sentimental value to someone who has that kind of money, but it's happening far too often to be isolated events.