Due to some changes this year, students who receive aid for books will now be able to "charge" the cost of books to their StanfordCardPlan. This is precisely to prevent students who are receiving full aid from going broke buying books before their financial aid is available. I suspect this means when the time comes to buy books, your son will just swipe their Stanford ID at the bookstore to purchase books.
"Effective September 1, 2009, the StanfordCardPlan will be offered to students only and will allow them to charge up to $1,000 per quarter at the Stanford Bookstore and other on-campus locations. The charges will be added directly to the student’s University bill. This change accommodates the needs of students who often must purchase books and other necessities early in the quarter before their financial aid is available. In order to participate in the new StanfordCardPlan, students will need to accept the 2009-10 Terms and Conditions of the StanfordCardPlan. The 2009-10 Terms and Conditions will be posted at this site by September 1, 2009."
Taken from:
Fingate - Overview: StanfordCardPlan