Hmm, are they going away to college? Will they be living in a dorm? You could do a "moving from home" care package like a big towel with a little travel bag... maybe little soaps, little travel size items that are easy to move back and for to the communal showers, ect. There are other themes like a dorm snack set which includes a plastic bowl, plate, utensils, maybe small rubbermaid items that can fit in a little fridge or microwave. How about a dorm first aid type kit with small tylenol, ibrprofen, band-aids. ect. I know some of this stuff might not seem exciting but when you are leaving home, those little things really make a difference. School supplies too... tacks to put up their pictures, mechanical pencils, the stuff you'd rather not spend your money on when on a limited budget.
If they are not leaving home, I'm not sure. I usually do cash because it seems the most helpful and I can't afford big items.