Hey RJ! Glad to see you chime in here!
I'll expand on what RJ says here. If you are one of the lucky few to eventually get a Broadway show, from what I've seen of the union contracts, it pays around $100k for a single horn gig (only tenor or bass), if you don't sub out much. But, reality is, you need to sub out enough to keep your subs working (who then return the favor when you don't have a show), and keep other contacts calling you, so that when your show closes, you have work. And, Broadway is fickle - there are long time Broadway players who are suddenly without shows, and new players breaking in. And subbing is very hard to get into - not impossible, but everybody and their mom wants to break in because it's the best non-auditioned regular gig in town.
Most Broadway shows, however, are not one horn gigs anymore - they usually involve doubles. Tenor/bass, tenor/tuba, and bass/tuba are most common, but euphonium shows up often enough as well. So, pay goes up (I think it's 30% bump for a double, and less for another double), and can approach $150k with enough doubles. But, you have to be skilled at your doubles - good enough that people will think of you as a player on that instrument, rather than someone who just doubles.
RJ is right in that if you can break in with the right touring groups, you can make a lot more on the road. But, that comes with sacrifices as well. If you picture yourself settling down with a wife and kids, touring is not really an option. And, if you don't stick around to build a network, when you are ready for that, it can be harder to have gigs on the calendar. I know a few guys who left the road and took day jobs because they couldn't get enough gigs once they decided to stop touring.
I will also echo RJ in saying if you want to play for a living, expand into electronic music. I've opened so many doors by expanding into keys that I'm probably going to increase my income by at least 50% in the next year to 2 years.
Couple of things to expect. You will work far harder for less money as a musician than you would at a day job, if you are going to make at least $40k a year. You will work the opposite schedule of 90% of people you'll meet, making it hard to maintain friendships outside of music. Any significant others are going to have trouble understanding what you do and how hard it is to take off time (since most people can take a day here or there and still get paid, where if you block a day off you are guaranteeing no chance of making money, which is a hard thing to do when you aren't making much). And, however much you love what you do, it is exhausting - period.
But, if you are dedicated, hard working, a self starter (there is absolutely no one that will push you to keep growing, learning, and expanding your skill set once you join the scene), and a bit of a risk taker (since there is a big risk in going freelance), you can make it happen. But it's not easy. I taught full time for 5 years - I'd say it's as hard to be a full-time teacher in Brooklyn (and not the nice parks), as it is to be a freelancer, and it pays better. But, I like this work more - I was a miserable teacher. If I'm going to work this hard, I'd rather play.
