If you are going to be traveling to multiple national parks, you should consider the $80 season pass. Many of the big parks charge a $25 entrance fee. This could be well worth it if you were going to do a road trip in Canyon Country. Also, they have a Senior pass that is $10 a year.
One last thing from the link below you can go to find a park. Each park has a fee section so you can research in advance it this is worth the money.