In keeping with the tradition of the Buddha Dharma, these classes are not offered for profit. Instead, they are shared in the spirit of dāna, or generosity. In many Eastern traditions, teachers, monks, and nuns are supported by their communities through offerings of the Four Requisites: food, clothing, shelter, and medicine.
Here in the West, such systems of support are still developing. A suggested dāna of $20 per class is offered as a guideline—roughly equivalent to the cost of attending a movie or sporting event. This contribution helps cover costs and allows the continuation of classes, even when support may be uncertain at times. All donations go directly toward sustaining the teaching and making future classes possible.
There is no obligation—only the invitation to give, if you are moved to do so.