Oil finishes lower for the week

Oil ended the day below $83 a barrel on today, finishing down about 4 percent for the week. That could spell more relief at the gas pump.

The national average for retail gasoline is $3.59 a gallon, according to AAA, Wright Express and Oil Price Information Service. That's down 10 percent from this year's high of $3.98 on May 5.

Gas could be around $3.25 a gallon by Labor Day and may drop as low as $3.15 by the end of the year, according to Fred Rozell, OPIS retail pricing director.

While gas may be headed lower, it's still taking a big piece out of household income.

The median U.S. household income before taxes is almost $50,000 a year. In July families spent about $374 a month on gasoline, or around 9 percent of household income, according to Rozell. For the year, monthly gas expenses average about 8.4 percent, compared with 6.7 percent in 2010.