Cheap RV camp ground in Southern CA

All good advice above and also check out the San Mateo loop in the San Onofre campground (Reserveamerica)which is closer to you. Not on right on the beach, but quiet, very clean and great for kids. Lots of families with kids camp here as it's not known as a "party campground". Lots of shade from the big trees. You can hike a trail to the beach, about a mile away. Non hook up sites are about $28 and water and power sites are about $48. We love this CG because you can usaully get a site there but book well in advance. Most beach sites book up about 6 mos in advance so you need to plan waaaaaaaaaay ahead for these. San Mateo's our old realiable fallback CG. Emma Wood, Dockwieler, and others posted above are all great but book up very fast.