Just some quick info man from someone just a little bit older than yourself.
My first job was at Boomerang's, I worked there as a dishwasher at age 14... I put in a million applications, followed up with every one and only got hired for one. You seriously have to apply for every job you can think of. Also, call and follow-up and ask them where they are at in the hiring process. Make sure they know you are really interested in the job. There are tons of teenagers out there, you really have to make an impact for them to be interested in you. Unskilled teenagers are expendable, make sure you know that...
I can relate to your problems, I bought my own car at 16, a 1995 Toyota Tercel for $1000. I loved that car to death because I paid for it...
For reference I did the steer clear program and had good grades, my insurance was about $170/month... Now at 21 with a clean record my insurance is about $135/month.
I worked at various restaurants until I graduated high school and was lucky enough to land an internship at a defense contractor. I am now a software developer there and made enough to move out on my own at 18...
Just apply everywhere, work hard and you will be able to get the things you want...