When I stop in a convenience store for a cold drink or other small item and they have a $5 or $10 minimum for card purchases, I pay cash. My favorite small business take-out place still has a $10 minimum because the CC companies charge them ridiculous fees for card processing and as their margins are thin, accepting cards for small amounts hurts their bottom line.

Most vendors at local farmer's markets are cash only, as are many vendors at street fairs/festivals/etc.