If you offer an open class for beginners you can expect them to pay about $10 for a drop in lesson. However, if ten people show up you're making $100 an hour. Not too shabby.
If you're offering classes through a studio you can probably charge $400 a season (Sept. thru May) plus any choreography charges.
Private lessons or smaller group lessons are more.
I charge $40 an hour for solo choreography, $30 for duet (each), and $20 (each) for trios and small groups.
Large group classes work out to about $15 an hour over the year.
Depends how good you are, and how badly people want lessons.