(Adventure National Parks by Taylor Rose)
If you're a senior citizen, you can visit all of the national parks for only $10 thanks to a lifetime pass available from the National Park Service. That being said, if you don't have one already, you might want to buy one as soon as possible because the prices are about to go up 800% on August 28. Given that each visit to a national park is $30, even an $80 pass will pay for itself after a few visits, but even so you might want to grab that $10 pass before it's too late.