Can you repair a Garmin GPS, mounting clamp has cracked

Depends, if it still in manufacturers warranty they will give you a free of cost same new product right away. I got my broken paper shredder replaced after few months of purchase. You gotta have the original receipt with you. Even if you don't have that they can pull it from system using your credit card used for that purchase.

Best Buy will sell you a new one they want repair one.