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.

A national consumer group backed by several educational organizations yesterday 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 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.

About 15 states already restrict or ban credit-card marketing to students on campus, said Matt Hamill, director of advocacy for NACUBO, the National Association of College and University Business Officers, one of several groups that joined in a campaign announcement teleconference. Congress also is considering a measure intended to keep students from taking on too much credit. Some colleges also ban marketing on campus, but Hamill could not say how many.

Organizers said many students need credit cards, but they still want colleges to take a more protective stance.

Brett Thurman, student government president at the University of Illinois-Chicago, said the administration there keeps card companies off campus, but at least one company passes out free coupons for a sandwich shop just off campus. When students arrive, they are given the actual coupon if they sign up with a credit card representative.

"He'll hook up anyone who comes in the door," Thurman said. "Even though universities are taking a really strong stance in many places to avoid this kind of abuse, the industry is trying to find a way around it."

Many colleges have affinity agreements with credit card companies that give schools money or a share of transaction revenue in exchange for an official stamp of approval and access to names. Generally, such arrangements are with separate alumni associations, but in some cases they give companies marketing access to students.

The coalition portrayed credit card debt as a growing problem in an era of rising tuition and expenses for things like textbooks, though some research suggests students may be handling debt more responsibly now than they did in recent years. The latest national survey from Nellie Mae, a student loan company, reported that 76 percent of undergraduates had credit cards in 2004, down 8 percent from 2001.

The average outstanding balance was $2,169, down 7 percent from 2001.