Originally Posted by Efrem
I concur with the advice to tip anyhow. It's not the bartender's fault that you don't have to pay cash for the drink.
Same here.
In the United States, bartenders and waiters depend on tips for a living wage.
$1 per drink is a good guideline, though there's certainly nothing wrong with a bit more than that, especially if you don't have to pay for the drink in the first place.