HOUSTON — Gasoline prices are tumbling just in time for the holiday shopping season to begin.

Consumers can thank the tentative reduction in tensions in the Middle East and swelling supplies of domestic oil for their good fortune, and energy experts say prices could fall further if negotiations between the West and Iran progress.

The cost of a gallon of regular gasoline has dropped by 6 cents a gallon over the last week alone, in line with a steady swoon through the fall that has brought prices to their lowest levels in three years.  Read more