Map updates cost $? Is this a standard thing for consumer GPS brands?
Yes, they do. Garmin does map updates once a year, they cost about 85$. You used to be able to load onto two units. No more. They got cheap and you can only use the map for one.
I usually update once every two to three years for my ground based GPS's. My air based ones get updates every year. (No, the sky doesn't change, but routes, airport frequencies, etc, etc change on a regular basis. )