Alamo: 1-800-732-3232 Avis: 1-800-331-2112 Budget: 1-800-527-0700 Dollar: 1-800-421-6868 Hertz: 1-800-654-3131 National: 1-800-328-4567 Thrifty: 1-800-367-2277 Enterprise: 547-7400 (rents to people under 25)