I teach in high school. History.
Here's the thing about teaching. You need a credential to teach high school or lower. I don't know what it is in other states, but in almost all counties in California you also need a credential to be a substitute teacher as well. I went to a private university until my baseball scholarship was up, then I transferred to a cheaper state school (Chico State), so the CSU system's criteria is what I know. There, you have to have a 3.1 GPA or better to get into the teaching credential program after graduation, along with a few extra classes that mean nothing toward your degree as prerequisites for the program. The program itself is two semesters of working at a high school or junior high with a teacher who basically acts as your mentor. You also have to take a class or two each semester one night a week. So you're working about 40 hours a week without getting paid a single red cent, on top of the time allotted for your class at night.
Once you have the credential though, you're in a really good position to get a teaching position right out of school. I had absolutely no problem finding a job and actually had to turn one down in favor of the position I hold right now.
Here's the thing though: I got really lucky in that sense. I graduated about ten years ago before going into the credential program, went to work in a totally unrelated field for a while, but also spent time as a youth league baseball coach and accumulated quite a bit of verifiable volunteer time with kids/teenagers through the Boys and Girls Club and volunteer time at a foster child agency. I also had letters of recommendation from an economics professor who I worked for on the weekends maintaining her property, the head of the Chico State history department, the head of the teaching credential program and a current teacher whose son is my best friend. I had excellent grades and interviewed well also. I also got lucky in that the school at which I did my student teaching had an opening the following year that they knew about in advance. So I had a lot of factors stacked up on my side of the ledger that most applicants didn't have.
Generally-speaking though, it is best to try to do your student teaching in the area that you want to teach in, because it gives you more networking opportunities and it also allows a potential employer to see you in action for a year first. I made quite a bit of money in my previous career before going back to school ten years later to earn my teaching credential, so I could afford to work part-time for cash under the table for a year while doing the credential program. But there are still financial aid opportunities while you are enrolled in the program if necessary, and many states will waive your student debts if you spend your first year or two teaching in a low-income area, which is well worth it.
As far as teaching itself goes, I LOVE it. I see bad teachers all the time, and I see good ones, and I would like to think that I am a very good one. You have to really have a passion for it, especially if you are teaching at a public school. There are going to be discipline problems, there are going to be students who don't give a fuck and so on. That part is frustrating, especially if you really understand the power of education and the opportunity these kids are throwing away by being apathetic about it. But if you have a real passion for TEACHING the subject and working with kids to better their lives, rather than just a passion for the subject itself, this really translates well to success as a teacher.
I don't really have discipline problems at all in my classes. For whatever reason, I have a really good rapport with the students because I respect them and I do not EVER underestimate their desire to learn, even the ones who think they're too cool to be there or whatever. I really think that it takes a special, or at least a unique, type of person to have this sort of effect on students while still maintaining control of the classroom and being effective at conveying information. You are not their buddy, but you are not an authoritarian either. You are an instructor whose job is to improve their lives and help them understand the power of education.
As for college professor, I hope you like school. You'll need a minimum of a master's degree to teach at a junior college and a PhD to teach at a university, plus you'll have to publish to stay relevant. I don't really know what college professors make compared to what I make, but I don't make a whole lot, to be honest. I have simple tastes and am smart with my money anyways, so it doesn't bother me and I am doing not only what I love, but what I am best at. I don't really think there is a price that can be put on that.