one of my xbox controllers just kinda broke.

The right analog stick does not work at all, so I was just wondering, should I just throw it out or do something else with it?

Fix it yourself if you know how to or just go and get a new controller.

I have 2 others, but I play split screen with my friends alot so I was just wondering if there is a way to dismantle and fix the controller.

Take it apart and check. It may just be popped off the button or something. Maybe ask gamestop.