You can check gasbuddy.com for some of the latest posts for gas prices. However, some gas companies offer as much as $.05/gallon off your purchase if you uses their credit card or as in the case of "Speedway" use a customer identification card which is not a credit card.
Check with your employer to see if they offer a Commuter Account. This nifty employee benefit enables you to pay for commuting-related expenses, such as public transportation costs (think: bus, subway, train, ferry, bicycle and vanpool expenses), as well as parking (either near public transportation or at work)…with pre-tax dollars.