COST OF LIVING OVERVIEW. Our cost of living indices are based on a US average of 100. An amount below 100 means Del Mar, California is cheaper than the US average. A cost of living index above 100 means Del Mar, California is more expensive. Del Mar, California cost of living is 338.50. Housing is the biggest factor in the cost of living difference. See the Del Mar housing market: Homes For Sale Apartments Single Family Rentals