According to AAA, the average prices of a gallon of regular gas in the U.S. rose 5.1% of 17 cents to $3.50 per gallon yesterday. This marks the first monthly increase since March and the largest July increase in at least 12 years. $3.42 was the average price of gas in July and was the third highest average price for July ever recorded. Gasoline companies are justifying the increase because of the higher global oil prices and increased demand for gasoline duringthe vacation season. AAA said it expects gas prices for August to be flat or slightly higher. Prices should begin to decline after Labor Day, but, there is no guarantee.