Gas experts chalk the drop up to the plummeting price of crude, down more than half (from $147 a barrel in July to $70 a barrel now).
For reference, if you have a 12-gallon tank and gas costs $4.10 a gallon as it did over the summer, you pay about 50 bucks to fill up. At $3.10, you only pay 37 bucks to top it off . . . putting an extra $13.00 in your pocket.
