If you get kicked out that one possibility you'll need to handle, but leaving home on your own and becoming homeless is another issue altogether. Trust me, you're not going to live too long on $200. What kind of education do you have? Do you have a job? You mention self-harm, that might mean seeing a therapist, any chances your parents would get you to one for that issue, then you might be able to bring up the gender questioning. Unless your in some real physical danger at home, you're best off not to leave. In the meantime, from what you're going through at home isn't half as bad as living on the streets without a job or any income. What do you plan to do in the future to earn a living for yourself? Do you think you might need to transition? That's going to take a lot more money you'll need to save up.
As I said, unless you're in physical danger at home, slow down, see if there's some way of seeing a therapist who can help you with the more basic issues, make a plan for your life. Chances are you've got a good 50-60 years ahead of you and you and going to have to start taking care of you.
Sorry, if this comes off seeming a little harsh, but it's nothing like living on the streets.
Wishing you the best.