if it is under $10 I use cash. It frustrates the heck out of me that none of the clerks know how to cound back change.
Used to laugh at the kids in the store I worked in when the power went off - they could not make change. They used calculators, pads & pencils anything to "figure" the change.
To this day, when a clerk hands me money, I count it back to myself to make sure it is correct.