We paid $50 per couple per week last year for a 1000 sq m camp site right on the beach in one of the most beautiful places on earth up in the North West coast. Absolutely no facilities whatsoever, but worth every cent, I reckon it was cheap. We stayed for 7 weeks had a world class left to surf, awesome spearfishing and diving and perfect for the kids on the beach.
I know what you are saying though, some Nato parks are ridiculous at $10 per night per head, a bit steep when all they supply is a hole in the ground.
Good winds,