I did a lot of research around web and mobile world to pick a useful app which can track car expenses, generate reports and show us the real picture of money burnt on car. Well, few years back I have created the google spread sheet to enter data from mobile / web and show graphical results. I found a better way this time and it is a mobile app which helps you to enter and sync the data between mobile app and web site. (It also tracks the real time trips)
Its nice and simple, just download it on your phone and give a try, its free as well as paid for pro version.