California registration fees are pretty pricey but I guess not the worst. But, it's the sales tax that really reams you. Pretty good system California has. They get the original sales tax from the person who bought it new and then they get sales tax revenue every time it's sold to a new party.
Also, California's smog emissions make things more expensive. If you want a catalytic converter that has the California stamp of approval, you're going to pay a hell of a lot more than one that is ok for the other 49 states. And, the catalytic converters that don't have the California stamp will allow you to pass a smog test in California. But, If you install a non-California catalytic converter and the tech doing the test notices it, you'll be failed on the visible inspection.
I enjoy living in California but I'm starting to think I'm going to abandon ship when I retire. It's just way expensive to live here.