Traditionally, the teachings of the Buddha have been offered free of charge. In return, students and other laypeople support monastics and lay teachers with donations. The Pali term is dana, which translates as generosity. This symbiotic relationship allows teachers to continue teaching and students to receive the teachings, regardless of their financial situation. With a few exceptions, the trend in the United States, particularly on retreats, is to charge for attendance. I think it is an important tradition and never charge for the teachings. Your support is greatly appreciated.