For those who are looking to head to Big Sur for the weekend but don't have a reservation, Andrew Molera is a great first come first serve campground right by the beach.
Andrew Molera is about 27 miles south of Carmel and one of the first State Parks you'll hit heading down the coast. There will be signs for the Park as you approach and the main parking lot is only a couple hundred yards from Hwy 1. There are a number of hiking trails and activities to do around the park if you want to just hang for the day. For those who are interested in camping, it is one of the few first come first serve spots a long the coast which is very nice since who actually plans camping trips that far in advance.
The campground is about a half mile from the parking lot so it's not quite car camping nor a true hike in spot which is a little unique. So if you can fit most of your things into your backpack then great, but if not, plan on taking a couple trips back and forth to the lot. The trail is quite flat for the most part and runs next to a little creek which will later dump out into the ocean.
The campground is essentially an open grass field with a few big Oaks scattered about. There are about 24 spots I believe so if you are planning on just showing up and hoping for a spot, make sure you do it as early as possible. Each spot is pretty spaced out and has a picnic table and fire pit. There are a couple well maintained bathrooms as well on the property.
Once you have set up camp, continuing on a long the trail past the campground, you'll eventually run into the beach about a mile away. The creek runs right into the ocean so you'll have to wade across it to get to the main beach, or you can take a side trail up to the bluffs and enjoy the view from there.
For more information on the state park, check their website: http://www.parks.ca.gov/?page_id=582