I'm sure it's changed a great deal since I took lessons hahahaha, but I imagine it depends a great deal on the teacher. An accredited business with a licensed instructor would probably bring in a lot more than a talented dancer in her living room. And it would also depend on whether or not you wanted to charge per lesson or if you wanted to hold an actual course, say, 16 weeks for a certain cost.
Why not call around some of the local dance studios and see how they charge?