The problem with card use that most people don't seem to know, or understand, is the merchant accepting the card has to pay a transaction fee to swipe the card (10 to 25 cents) plus a percentage of the sale based on the type of card, rewards cards being the highest. So  for a dollar sale the merchant is making in profit 50 cents, the fees come out of the 50 cents. So carry some cash for small purchases, like under $5.00 Credit cards are not free!