Should I be signing up for a monthly phone plan when I don't have a steady job and I'm about to start grad school

The ($45) plan offers 350 min. and other very good features (unlimited this unlimited that). I'm wondering if I made the right decision in choosing a pricier phone plan (that I realize will add up) when I'm about to start grad school in the fall. The school's location requires me to live away from home, so I'll be dealing with those expenses. On other hand, I'll probably use the plan's features later in life if not immediately. Is there a "should/should not" answer?