A debit card is a bank-issued card that when used in combination with a pin number allows a consumer to pay for goods instantly, much like using cash.  Some banks now offer the same debit cards with a major credit card company's logo - such as MasterCard or Visa - allowing you to use your debit card as a credit card.  This can be tricky as sometimes the establishment will charge you immediately for the purchase as others can take up to 3-5 days for the transaction to get posted to your account.  These banks also have rewards programs for when you use your debit card as credit such as Suntrust's Sunpoints program - giving you 1 point for every 4 dollars you spend.

Debit cards also can give you the opportunity to get cash back at certain retailers without a fee - such as Publix - where you can take anywhere from 1 penny to 100 dollars depending on locations.  This is a feature that credit cards do not offer due to them not being tied to a checking account. 

Credit cards are tricky, you can put charges on them anywhere that permits, but your payback terms vary, sometimes making items much more expensive if not paid back at the end of each month.  APR's can be very deceptive - especially when introductory offers are made and minimum payments lure young and unsuspecting consumers into putting charges on their cards that they would not normally make.

My advice would be to stick with a debit card from a major financial institution, as a good philosophy is - if you can't afford it with cash, you can't afford it at all.