On the other hand, many 18 year olds are not ready for credit cards and do succumb to overspending.
From USATODAY.com :
Easy credit can mean long-term hardship for college students: "College students tend to have less financial experience than older adults, making them more susceptible to these pitches....Nearly a dozen states, including New York and California, have made it harder for card companies to market on public campuses. And a growing number of colleges, on their own, have begun to impose restrictions."Of course the credit card companies do not want to lose this market.
So what to do? If you are a college student who is mature enough to use (and not misuse) a credit card, I would recommend highly getting one to build credit and for ease of use. However, get one with no fee and pay off the bill completely every month. If you find this progressively more difficult to do, stop using it until it is paid off.