I worked for a company in 2004 that was a spinoff of a professor's project to create randomizable equations linked to a text book. Students would get a unique key/ID from their textbook, and log into our system to take practice exams and work on examples. Each question would be unique, and hopefully pedagogically correct.
Textbook publishers loved this idea, especially the fact that it required a unique key for each student. We had all of the major college textbook publishers as customers, either using our hosted system or licensing our software to use on their own web servers. If I recall correctly, we charged around $20-30 per student.
Eventually we were acquired, but I assume the software is still being "marketed" to the students.
The professor's project was funded by a DoE grant, and then he turns around and commercializes it with the explicit approval of the university.