How do tip a barmaid?

Question

I go out by myself, a dollar for the first beer depending on the service they'll get more or not for the second one. Yesterday I had a tab, 3 beers, bill was $9.50. I put 12 on my debit card.

A barmaid said a dollar every drink, but she's the cheapest tipper I ever met, to the point of being embarassing.

Answer 1

What you tipped is just fine...

Answer 2

cash is good

Answer 3

A couple dollars after a few beers would be nice. I don't think a tip everytime is necessary.