I've taken lessons from a former four stroke world champ for $60 an hour. My best advice is to break the lessons in to two hour sessions when you are going one on one. It's just too much constant riding to focus and get your money's worth. If you are in a class of 15, it's a whole different story because you get less reps of each segment and more time to rest. I know kids can go non-stop for 3 or 4 hours, but their retention and concentration will go way down toward the end of the session.