Most of the specialized license plates come with an extra fee, and it varies depending on the plate. That extra fee also goes to different beneficiaries depending on the plate.
The new National Park policy is called the Alternating License Plate System (ALPS). The purpose of the policy is to cut down on traffic inside the park.
Personalized license plates in Idaho are a highly governed item. They can't be vulgar, offensive, hateful, or profane. That doesn't stop people from trying.