How much do you charge for your bandwidth?

I have a customer with a fairly small site, around 250megs, but starting to use a lot of bandwidth... Not really sure on how to charge him just per bandwidth...

usually its $1-$8 at most hosts per GB some charge more some charge less

i charge $6

Really you have to consider your cost. If you go over on your usage, what's your provider going to charge you? Do you want to make a profit on overage?