Have you explored all the possiblities using "student" discounts? Age may or may not be a factor.

In other words, by speaking directly with your carrier and explaining your rather unique situation, they might just be willing to be creative and come up with some sort of pre-paid bulk discount.

It's worth a try, no?

In fact, it worked for me when I was a student at HBS and commuting from NYC to Boston every week.