There was a discussion on credit cards vs cash in the movie thread below but it seems to me to deserve more discussion.

I accepted cash or checks only when I first started selling my beef at our local outdoor Saturday farmer's market maybe 20 years ago. After requests from customers I started accepting credit cards using Square software and an I-pad on cell phone signal. 

Sales went up when I accepted credit cards, I spent much less time than handling and depositing a lot of checks. However expenses went up also, somewhere around 3% of sales for cc processing at the time as I recall. So from a vendor standpoint it was a mixed bag. I raised prices slightly for everyone to cover the processing charges. 

Today a retail business almost has to accept credit and debit cards. A couple of my kids never carry any cash!

Card ads promote "cash back". As I try to discuss with my family, "Just where do you think that 'cash back' comes from?" It's your money in the first place because businesses raise prices to cover the increased costs of accepting and processing credit card payments. Yes, accepting cards can  increase sales and reduce some handling costs but that's a very mixed bag.

In our town I see more and more businesses, especially restaurants, offering a discount if you pay in cash and they don't need to pay what is often a 4% or more fee to the bank on credit card transactions. I like to see that. Otherwise they have to raise prices for everyone to cover the cc processing costs for some of their customers. 

In effect cash customers end up paying more to subsidize the processing fees and "cash back" of the credit card customers.

Gas stations are a different situation in some ways, few people carry enough cash to pay to fill up a car or pickup at today's fuel prices. However the fuel is still priced higher to cover cc processing. I am happy to see some highway truck stops showing a significant difference in diesel prices with a significantly lower per gallon price for cash payment compared to credit card payment.

FWIW, in general, if a business offers a discount for cash I try to pay cash. If a business offers the same price for cash and credit cards and I have to do business there I use a credit card. I hope more businesses start to offer a discount for cash payment.

ETA: the cc processing fee and discount for cash however pales compared to the 20-30% credit card interest rates if you don't pay in full every month!  Another advantage to paying cash vs using a credit card for some folks is using cash helps you to control your finances.