The beginning of the school year -- already a stressful time for kids and parents -- is often made even more difficult by all the purchasing pressure, from long lists of school supplies sent home by teachers to ads promoting fashionable new wardrobes for children. In 2003, Americans will spend $14.1 billion on back-to-school items, with $6.5 billion of that going towards clothes. Make sure the contents of that backpack are as green as its outside. In addition to the dent in parents' wallets, there are environmental and social costs to all this school-related spending. Long before little Chloe or …