As noted below, if it's a RealtyTrac "listing," it's fake. Most aren't for sale, and many never will be. Those that do go on sale will be priced a lot higher. I've investigated a number of such listings around where I live and work, and I haven't found one yet that's legitimate.
In some cases, you can buy properties for very little--in Detroit, for example. But there are reasons why--there's almost no demand for such properties.
Sometimes you'll see tax sales of property at very low prices. That's usually because the property is in terrible shape or you can't do anything with it. For example, it might be a lot that's too small to build on, or a landlocked slice of land with no access to the road.
Hope that helps.