Fees for prepaid debit cards have shifted in the last year, with some transaction charges becoming less common while automated-teller-machine fees rose, according to a new study.

The level and types of fees charged on prepaid cards vary widely, according to an annual study by Bankrate, released Monday, which looked at 31 common prepaid cards. In general, while ATM fees are rising, many fees for using and servicing cards have declined, Bankrate said.

"Many of the higher-fee cards seen in the past have been marginalized or even discontinued, while the newer entrants often have more transparent fee structures and in many cases, avoidable fees," Greg McBride, chief financial analyst for Bankrate, said in the news release.

Twenty-three of the thirty-one cards have monthly maintenance fees, which range from $9.95 for a prepaid MasterCard offered by the Bancorp Bank, to $1 for the American Express Serve. Eight banks will waive the fee under some circumstances, a slight increase over last year, Bankrate said.

Fifteen cards also charge an activation fee, ranging from $1.88 for a Wal-Mart-branded card offered by Green Dot Bank to $9.95 for a prepaid Visa from the Bancorp Bank. More prepaid cards than last year allow users to waive the fee if the card is activated online, Bankrate said.

While activation and maintenance fees have become slightly less common, ATM fees are up. All of the cards charge fees, ranging from $1 to $3, for using out-of-network ATMs. Of the twenty-two cards associated with a bank's ATM network, sixteen don't charge for using an in-network ATM, while the rest charge fees as high as $2.50, for certain cards issued by Metabank and the Bancorp Bank.

Twenty-five of the cards also carried costs for checking the balance at an ATM, which ranged from 50 cents to $3.