The easiest way to save on car shipping is to be flexible about times. Many shippers charge extra for deadline jobs, and reserve their lowest rates for those who can wait an extra couple of weeks to get their vehicles. This lets them combine shipments going to the same general area.
If your vehicle is older or less valuable, you may save by going with an open carrier rather than a closed one. This does subject your car to the possibility of road damage, and in the case of motorcycles is not advised for security reasons.
Finally, some companies charge more for door-to-door service, and less for delivering the vehicle to a terminal near your destination.