Gas Trip will allow you to see the cost of your car trip in real time. Simply load up the application, specify your MPG and watch as Gas Trip finds the lowest price of gas in your area and determines how much you are spending based on your speed and distance traveled. You can use this to help split the cost of a carpooling trip, to expense travels for work, to find the cheapest gas in your area with directions, or to simply gain instant knowledge on how much you are spending on gas for the trip you are on.
Gas Trip isn't very
Gas Trip isn't very intuitive and I've never gotten it to find gas prices properly. Not worth the download.