How can I purchase products online from the Apple Store with a debit card?

I don't have a credit card and I don't know how to put in my debit card info into my Apple account. There's only a "Credit Card" option. How do I put my debit card info into my Apple account? I also have an iTunes store account as well. Please give me step-by-step instructions. Sorry. Thanks.|||Just put your debit card information in as if it were a credit card, it will work just fine. (You can do this at the grocery store, too, if you'd rather sign than insert your debit PIN.)