Here in Japan I usually see those for sale at the equivalent of $1-$3, but many artists give them away or sell them for just the dollar because they are more interested in getting their stuff read than making money off of it.
Personally... unless the art was amazing I wouldn't pay for a xerox copy comic. They are hard to keep track of and tear easily, so for me it's not worth my money. Maybe if it was super rare art from a famous series or artist, but I don't really buy those at cons or comic events. For my own work, if I want to hand out a flier it comes from my own dime.