Because online courses involve lots of reading and discussion, you can learn a lot simply by observing a course.
If you don’t have time to do all the assignments or the money to pay for a full class, consider auditing the course for just $100. (Senior citizen and HS scholarship discount does not apply if you are auditing.) Although you will not receive any credit for this course, you will have taken an opportunity to learn more about a subject and to become a life-long learner. A select number of audit spots are available for each course. Sign up early to reserve your spot.