Nope, Nuvi isn't made for a bike. Lowest price I could find for a Zumo without a mount is $600.:scaredThe Garmin Nuvi is not motorcycle specific, the Zumo is because it is water proof and vibration proof. The Zumo is considerably more expensive.
This is my Zumo 550 mount
agreedAmazon has some of the best prices for Garmins.
You can find them elsewhere a little cheaper sometimes, but the Amazon return policies and their customer service cannot be beat.