Current U.S. military members and dependents in the Army, Navy, Air Force, Marines, and Coast Guard as well as Reserve and National Guard members are eligible for a FREE Annual Pass to the National Park Service.
This pass, which is normally $80, can be obtained in person at Federal recreation sites that charge entrance or standard amenity fees. It covers entrance to Fish and Wildlife Service and National Park Service sites that charge Entrance Fees, and Standard Amenity Fees at Forest Service, Bureau of Land Management and Bureau of Reclamation sites! There are around 100 parks that charge for entrance so this is a nice deal!
It admits the pass owners and any accompanying passengers in a private non-commercial vehicle at per vehicle fee areas, or the pass owner and up to additional 3 adults at sites that charge per person!