I know when we used to can in Indiana (Muncie), we would usually have a few people that would give $10-$20. Usually depending on the cause. What I always thought was interesting, was that many times the people who really went out of their way to donate were the one's who looked like they could least afford it.
My most memorable experience though was once having a "drive-by butt-grabbing" while I was standing in the median once!