I have a rogers rocketstick, and agree with what everyone has said. its 35 for 1gb. depending on what he's doing that goes fast. if you're on youtube, and hour later you'll be at the max.
its not a great option, i use it for work checking mail and staying online when i'm at cottage and away from home or office, but as an everyday means of browsing the fees will kill him.
tell him to get a blackberry or iphone and browse there, much more economical, 6gb for 30 bucks, they screw you on the rocketstick.