Yes. Most aftermarket GPS models are easy to move between vehicles. If this is your plan, you'll need to give some thought to the mounting system and power supply.
Temporary mounting systems such as a suction cup or friction mount work with pretty much any automobile. Models powered by batteries or from a cigarette lighter provide the most flexibility.
More permanent solutions can be used if you install a mounting bracket and direct power connections in each vehicle. Extra mounting kits can often be purchased as accessory items.