I know for a fact that this job pays very well because I have many friends who are performance and theatrical makeup artists. I've even paid them for some work before and they weren't cheap. If you want a professional production, you have to hire them. It's that simple. With that kind of demand comes some very high wages. You do have to consider that you have to buy your own makeup, but that is often considered in the rate, or it's negotiated in the budget if something like heavy prosthetics are needed. Those things are not cheap, and they can take hours to apply.
The best places to work will be the East and West coast, though there are productions all over the United States. Still, you won't find quite the work you will on the coasts, though that means competition is also higher. The best ones can charge a great deal for their services, and those in the top 10% earn about $122,000 a year.