NEW YORK - American Express has entered into new territory for the financial firm with its new prepaid card, USA Today reports. The prepaid card market has exploded in recent years as more people who don??t have bank accounts or who don??t want traditional credit cards seek alternatives for online payments and other uses.

Currently, more than 17 million in the United States don??t use bank accounts. Experts predict that number could blossom as banks begin charging more for checking accounts to make up for the reduction in swipe fees.

Prepaid cards give the "unbanked" access to a safer and less costly alternative to pawnshops and check-cashing places, with many prepaid firms letting cardholders direct-deposit paychecks onto their prepaid cards.

Consumer groups contend that many prepaid cards have high activation, reloading and other fees that can eat into the card??s balance. Florida??s attorney general is investigating allegations of unfair and deceptive practices on five prepaid card companies.

Tim Chen, CEO of NerdWallet.com, said consumers need to carefully check out reloading fees and withdrawal costs before deciding on a card. Also keep in mind that American Express cards are not accepted at some retailers because of the higher transaction fees associated with its use.