Sorry, I have to disagree, I carry a debit "check" card so I don't have to carry cash. When I need cash I go to my bank and take some out with my debit "check" card. It's more convenient for me than carrying around a wad of cash. Oh, and my bank does not charge me to use the card unless I use another bank's ATM.
I also carry credit cards and use credit cards for most purchases.