I found in the Tulsa newspaper "The Tulsa Parks Fun Guide". This is a booklet that is distributed 3 times a year (spring, summer, fall/winter) that lists affordable classes and special events. All the classes are available through the Tulsa Parks community.
These classes are very reasonable and since I've wanted to take a digital photography class I thought this would be great! It was very affordable $90 for 7 weeks. I went to my first class last night and I'm anxious to see what I will learn.