Most of the places that have campgrounds at the beach are CA State Parks and so the rates are very low. Check the state website for information on the parks. In addition to some mentioned there is a great place near San Simeon.
The Gold Bluff beach campground has a maximum vehicle length limit that restricts its use to truck campers and tent campers. You will not find a wilder beach in this hemisphere. Also an elk herd in this area as well as a second one
up on the bluff where there is additional camping available.
Also private RV parks at Marina and Moss Landing that are steps from the beach and the ocean. At Moss Landing you can walk to good places for breakfast, lunch, and or dinner (seafood, Mexican, Thai).