I think $1/beer is perfectly reasonable. I've noticed the price of beer has skyrocketed at the pubs/bars, but assuming the absolute high end of $8 per beer, that's still a 12.5% tip which seems fine to me.

I usually tip somewhere between 10% and 15% on a good day. People can call me a cheap bastard if they want, but it's already getting crazy expensive to eat out and that's 10/15% on top of the higher alcohol/food prices. The waiters/waitresses always look disappointed. I've learned to stop worrying about it. It's either that, or I stop eating out all together which is zero dollars in anyone's pocket.