If you don't use cash back credit cards... you are losing out on a lot of money! I NEVER carry cash. I pay for everything with a variety of credit cards that get me various amounts of money back via cashback offers. (Including paying any bills that allow me to use a credit card... i.e. cell phone, water, car/homeowners insurance, alarm service, vehicle registrations, etc.... why not get a discount off my utilities!?)
I get 5% back on things like gas, groceries, restautants via Discovers quarterly 5% cash back offers. You can earn up to $75 in FREE money if you spend to their limit of $1,500. I get even more back because I normally cash any Disco cash back in for gift cards that net me even more money (i.e. use $20 of Disco cashback for a $25 Bass Pro gift card. Most of which I do on the fly/in the store so I don't have gift cards laying around unused or getting lost.)
I have other cards that get me 3% at Drug Stores, grocery stores, restaurants, gas (when it's not a Disco 5% quarter). I get 2% at Sam's club... and then I have another "all other" purchases that I get a straight 1.5%.
I don't pay them off monthly... because I'm too anal so I go and pay them once they go from pending to being an actual charge. That's NOT CREDIT CARD DEBT! That called smart use of credit cards to make money!