Gasoline prices plunge 50 cents a gallon during the last month in Southern California. Gasoline prices are plunging in California, falling 50 cents a gallon around the Southland during the last month. Getty Images / June 28, 2012 By Nancy Rivera Brooks June 28, 2012, 1:13 p.m. Southern California drivers are paying about half a dollar less per gallon at the pump than they were a month ago. The average price of self-serve regular gasoline in Los Angeles County was $3.793 a gallon Thursday, 13.2 cents less than a week earlier and 51 cents lower than a month ago, according to the Automobile Club of Southern California's Weekend Gas Watch. In Orange County, the average was $3.751, down 12.9 cents in a week and off 51 cents in a month, the Auto Club said. San Diego's average of $3.774 fell nearly 12 cents from the previous week and 51 cents from the previous month. "Fourth of July travel by Southern Californians is projected to increase 5.2% from 2011, and these gas price drops will put more money back into travelers" budgets," Auto Club spokesman Jeffrey Spring said. For the first time in 2012, the average gas price is below the year-earlier price, the Auto Club said, coming in at 5 cents lower than at this time last year. The average price in Los Angeles is down 60 cents from the peak for the year. The year-to-date average price paid in Los Angeles is $4.12 a gallon. The most expensive gasoline in California is being sold in San Francisco, where the average Thursday was $3.948. The cheapest was in Yuba City, where motorists paid an average of $3.693. The gas price averages come from the AAA Daily Fuel Gauge Report, which presents a daily survey of credit-card receipts from more than 100,000 fuel sellers around the U.S., tallied by the Oil Price Information Service. New car prices drop as supply improves Used car prices start to pull back from highs Car review: Nissan Altima loaded with style, substance