Would you like to run your own webserver? Would you like to run your own mailserver? Would you like to experiment with Internetworking but can't find or afford all the right software?
Are you a programmer? How many languages would you like to learn, but you can't afford the compilers? Would you like to learn from high-end, well-debugged and thoroughly tested software? Do you want to learn low-level programming without buying a separate "Driver Development Kit"?
Do you want to be able to set things up to run automatically when you do certain things, or at certain times, but you can't afford the add-on Schedulers, and even if you could the applications you want to use aren't scriptable?
Given the time and effort to learn it, Linux will reward you with absolute raw power over your system and freedom from hangs, crashes, "illegal operations" and reboots.