They do offer real classes done through independent teachers, they are typically group lessons, but they are at a pretty reasonable price! http://classes.duolingo.com
For what it's worth, I use Duolingo (the app itself) as just another way to practice at the moment but feel that most of my real progress comes with a tutor that I found through Preply and eventually started private lessons with. Group lessons were a cheap way to get some more practice in though with other speakers.