The inter-agency America the Beautiful annual passes cost $80.[1]

[1]: https://www.nps.gov/planyourvisit/passes.htm

$80 a year. The disability, military, or age 62 will get you a pass that's valid for life, and only those who age into it have to pay anything at all.

Typically you have to visit three parks within the year to pay for it. If you live in the East, it's probably not something you'd get every year. If you live in much of the West, it's probably something you'd be crazy not to get every year.

In general, it's something like $20-40 to go into a national park--maybe for up to 7 days--though it varies.