transportaion

i am enlisting in the air force, and want to sign up for 6years which means after basic i will be E-3, I live in las vegas near the air force base and i always see air men riding around in nice cars i was wondering how do they afford it. I know that now if i wanted a nice car i will probaly be paying 500 dollars a month, plus another 500 for insurance. in the military do dealerships help u out with buying a car. and is the insurance cheaper. people tell me that once you are in the military, it's easier to get financed because they know that it is gauranteed money is this true. thank u in advance