yes, you're right. i haven't counted the road tax and insurance
yet, i usually rely on the 13month "bonus" to pay it. but i DO have
extra/side income of about $250/mth which i save part of it to
cover.
i do agree that if you're not earning much, don't buy a car.
in fact, the side/extra income that i have is necessary for me if i
want to live by better. 
you can say that i don't really need the car if that's the case,
and i don't have to earn that extra money just to cover.
but to me (and i believe it's the same for many here), that a car
is more than just a transportation tool. hence, i do enjoy driving
a car even though i know i have to work harder for it. 