Corolla,Brake fluid

My car has no brake fluid. I was told that I can't just put more in, because I probably have a leaky line. The car is old and has a lot of miles on it, so I don't want to put very much money into it. That being said, I don't really have enough money to get a new car either. Is it possible that my car just needs more brake fluid and there isn't actually a leak?

My car has 208000 miles.
My car has an automatic transmission.