Amazon offers the Garmin Montana 610T Handheld GPS Unit, model no. 010-01534-01, for $521.95 with free shipping. That's the lowest total price we could find by $17, although most vendors charge $550 or more. It includes a 4" touchscreen, 100,000 preloaded U.S. maps, 250,000 preloaded geocaches, and a 1-year BirdsEye Satellite Imagery subscription.