Your pay rate depends on a number of things one of which is whether you're teaching sessions or classes. Sessions are typically privates (one-on-one) or semi-privates (two or three clients per teacher). Think of these as appointments like personal training. Teaching sessions will typically generate more income than teaching classes but a lot depends on where you teach. 

If you teach for yourself out of your home you're keeping all your income but you have to make the investment of equipment. Many studios rent space for an hourly/monthly rate so you need to factor that into your pricing. Both of these options require you to find your own clients although some studio will pass clients on to you for an agreed upon fee. If you contract at a studio that doesn't rent, they will provide clients for you and pay you an hourly rate or a percentage. Either way the average session teacher can make anywhere from $20-$50 and hour.

Your income teaching classes depends on the place you teach at just like sessions. If you teach in a gym you typically get paid an hourly no matter what the capacity. Some gyms pay a flat rate plus a per head so if you're a popular teacher you can generate some bank. Teaching at a studio can pay you a flat rate or percentage. It's not as common to rent space to teach a class, it would take a huge following and it's easier to do it at your local community center or at the park for free.