PhD, Startup, or Career? 
CyberED: Get some "real world" experience first.  I got bummed out doing a Masters many years ago - got distracted by money making ops.  So 20 years later I'm back doing a PhD.  The topic is more practical and yet breaking some new ground from the academic perspective.Don't let money dictate your decisions.  Seek to optimise your experiences and that goes for life outside of IT & work. The startup option will teach you the most.  Just don't count on getting rich.  It so spoils the experience.