My parents didn't pay one cent towards my college education -- nothing for tuition, not a single book, not a penny of allowance. Of course, they really weren't in a position to pay much. I worked like a dog. I earned my first degree in five years (couldn't always manage being a full-time student) and my second degree two years later.
For my own children, I've put money aside and I expect to pay all their basics: tuition, meal plan, dorm room. I expect them to work full-time during the summers and part-time during the school year. By the end of the summer they should have a good savings account which'll pay for their textbooks both semesters (and give them a financial cushion), and their during-school work'll be their spending money.
I will probably do as others have suggested: send generous care packages occasionally -- or, perhaps, when they come home for a weekend, I'll have a nice box of goodies ready to go back. I'd imagine these boxes would include laundry detergent, canned sodas, snacks that they like but probably can't afford, a pack of new socks and undies. But those would be GIFTS, given when I feel like doing it -- they should plan for their own necessities.
I remember having literally NO MONEY for weeks at a time in college -- I mean, I remember not being able to buy a soda from a vending machine, I remember not being able to do my laundry, I remember wearing shoes with holes in the soles. While this wasn't pleasant, it did teach me to be VERY FRUGAL with my money; since graduation, I have always managed to avoid debt and stay ahead of the game financially -- I think a large part of that is that I was always forced to live within my means during college -- I had no safety net to provide me with little luxuries. I want my daughters to learn this lesson too, though I hope they can do it without going to the extreme as I did.
Assuming they live in a dorm/suite, they can't really get into trouble without having money. Their tuition'll be paid for the semseter. They'll have a meal plan, so they won't be hungry. At worst, they'll have no clean clothes and will have to say, "Sorry, I can't go out to eat with you all tonight".