good luck..it's harder than it seems.
just remember that when making your budget..be lenient. don't keep cutting it to extremes where you 'think' you can make due with this amount of $$. be fair to yourself (your young so it's not like you need to stress over paying bills upon bills.
proportion out a pretty fair amount of entertainment expenses and force yourself to keep to it. also remember that friends birthdays, graduations, dances, etc do happen and you will need to spend $$ on those events.
Even if you can save 50-100 a week--that's awesome.
good luck with it..hope you get your car