The person below who claimed that Wyzant takes 40% forever clearly didn't read at all. The have a system so that as you tutor for them your cut increases, until you're at 80%. And as others have pointed out, with the discount packages they offer the students, that means for some tutoring they actually receive nothing.
It is a great service. In less than two weeks I found two students and have made more money than I had budgeted for.
My only complaint is that the website sometimes is buggy for me, with having to reload pages multiple times occasionally. But this is a small complaint for such an awesome service.