In the coming weeks, millions of students will be returning to college and university campuses.    The air will be full of excitement as existing students settle in for a new year and new students look forward to a new chapter. Dorms will fill up with boxes and suitcases and the quad will fill with tables representing campus activities and student organizations. Campus bookstores will offer extended hours as students search for their books and materials. These students will spend hundreds of dollars, some over a thousand, this semester alone.  Increasingly, this spend will not occur inside the bookstore.