Tom,
There is a free education service that is provided by Blackboard. You cannot charge anything to anyone who uses the system through you. It is designed for teachers to provide coursework for students to access online. It is a message (email) system as well as an assignment and assessment service. It is really nice, and you can set up accounts for each of your students to login to his or her own coursework for each of the classes you create in the Blackboard system.
You can set up five classes for free. It is an awesome tool for teachers and education professionals to use to allow students to access coursework online. However, if you wish to have more than five courses, or if you want to charge a tuition or fee to students accessing your courses, the pricetag starts at $9500. Of course, if you are an institution or large education provider, it is well worth it. It is way more than what I need for my work, so I need to keep shopping around.
Here is the website if you would like to take a look:
www.coursesites.com