Best day of the week
False. If this were true wouldn't everyone be doing it? There is no best day of the week to make a pit stop at the pump, or predict when prices will dip.
There are several websites, locally our own guide to gas prices in your area, and nationally, GasBuddy.com and AAA's Fuel Price Finder — that allow you to canvass your town's stations without driving around in search of the best deal.