Students across the country are headed back to college, and millions of them will get financial aid disbursed on a debit card.

The cards are convenient and save money for the schools. But these debit cards can be expensive for students, who could see their financial aid eaten up by fees.

This month, the Federal Deposit Insurance Corp. announced it had ordered the nation's largest player in campus debit cards — Higher One — to return about $11 million to roughly 60,000 students related to fees the company charged for insufficient funds. Higher One, which is used by the Johns Hopkins University, did not admit to any wrongdoing but says student accounts have been credited.

It just seems that students have a big target on their backs, with financial institutions working all the angles to lure young adults. Credit card issuers aggressively pitched plastic to unemployed students for years until Congress halted the practice. And the loan scandal a few years ago revealed that some schools received kickbacks for steering borrowers to certain lenders.

And now, if students don't pay close attention, they can find precious aid dollars wasted on debit-card fees.

"This is another example in a long run of examples of banks targeting colleges as gatekeepers to young consumers," says Rich Williams, higher-education advocate at the U.S. Public Interest Research Group.

Students don't have to go along with the debit cards. They can opt to receive their aid in ways that are free — something students should explore before arriving on campus.

But this homework shouldn't rest on students' shoulders alone. Schools choosing to disburse aid through debit cards need to find the company that offers the best deal for students.

"They need to protect students, not exploit them," says Mark Kantrowitz, publisher of FinAid.org.

More than 9 million students now receive financial aid on debit cards, according to a recent U.S. PIRG report that is highly critical of campus debit cards.

Financial aid is first distributed to the schools, which deduct tuition and other fees. Any aid that's left over for books, housing and living expenses is then disbursed to the student — traditionally by check.

But as school budgets have shrunk, more colleges have contracted with banks and financial firms to disburse this aid through debit cards tied to a bank account. For schools, this is cheaper than issuing paper checks, but it's not always economical for students.

PIRG's Williams, who co-wrote the report on debit cards, says it costs $5 to $10 for schools to issue and mail a check. He says students on average pay $49 a year to use a Higher One card.

"This is a huge cost shift to students," he says.

The card sometimes arrives in the mail on the school's letterhead, leading students to assume that the school has selected the best provider, Williams says. Students are directed to the debit-card company's website, which nudges them to have their aid put on the card.

Though they don't have to use the debit card, many don't know that, Williams says. And some don't realize the debit card is linked to a bank account.

"They don't realize it comes with all the responsibilities of an account, including overdrafts," Williams says.

Students can choose to have their aid transferred into their own bank accounts. But debit-card providers don't always make that easy, Williams says, and the process can delay aid to cash-poor students by two or three days.

"Most students need money now," Williams says. "It's not an option for them."