We're interrupting our butterfly series for our gas price series. Since we discussed gas prices last month, the price for one gallon of unleaded has gone up 18-cents. Between December and January, we saw prices jump 24-cents. That's 42-cents in just two months! Good grief. Those who check in with SDP regularly know that I've been documenting gas prices for the past 11 months at the same gas station. To see the month-to-month documentation click the label 'gas prices' below.