I wish I could just buy an annual subscription to the national parks. Last time I checked, it was $85 a year. I'd happily 'donate' that on years I don't visit the parks at all. Just set up recurring billing!
If you have an REI membership, you can buy one online from them for the same $80/yr. They'll either mail it to you for free or you can pick it up in store within an hour if you live nearby.
You can also just walk in and get one in the moment. I get my annual parks pass every year from REI. Pays for itself in no time with the car/parking situation alone.
But, nope. Gotta buy one every year.