With small incomes and big bills, college students make a prime market for credit cards. But critics say the card companies take unfair advantage, luring students with free T-shirts and food – then snaring them with high interest rates.

Yesterday, a national consumer group backed by several educational organizations launched a campaign to persuade more colleges to crack down on credit-card marketing to students. The coalition wants schools to take steps ranging from prohibiting card company giveaways to blocking their access to student lists.

Organizers also promised to do their own consumer education and counter-marketing, setting up tables near where cards are being hawked and giving away their own trinkets and food, like lollipops with the message “don’t be a sucker.”

“College students are vulnerable, they’re already hammered by the high cost of education,” said Ed Mierzwinski, consumer program director of the U.S. PIRG Education Fund, which is leading the effort. “Cards seem like a solution but they can become a trap.”

Ken Clayton, managing director of the card policy council of the American Bankers Association, which represents card-issuers, said his organization shares the goal of better educating students about credit, but said that overall, students use credit responsibly, and pay their balances in full at the same rate as the general public. He also said three-quarters of students get cards through general advertising, not campus promotions.

Credit cards “serve a very valuable function, whether it’s to buy books, airline tickets home, or pay for emergencies like when your car breaks down,” he said.