You have been living in the city for quite some time. And you are able to hang in there all by yourself. So far so good, you have got some supplies and eluded some zombies, but when you turn on the TV, you found out that the nearest camp has been overcome by the zombies and they are about to live. This will be the last chance to get out of the city.
Buy yourself a car and some fuel. Drive your car as fast as possible and ram those undead. You earn money based on the distance you covered. You can use the money to upgrade your car.