Does your school offer consumer economics or other economics classes? You could seek out the teacher even if you aren't in the class (yet, sometimes that's a senior-year class). They could at least recommend a book, website, or worksheets to get you started. Or I found this site. Not sure how much of this information you could use:
http://www.themint.org/teens/I haven't touched on investing or 401k's too much myself yet, I'm reading about it, and I agree it's confusing to get into! (I didn't take the fast-track to retirement, I'm 25 and went to graduate school after college, which doesn't pay a lot or have 401k's).
But, here's what I'd tell my sibling/cousin/younger friend:
-Money: The basic rule this site/forum and any site worth its weight will tell you: earn as much as you can and spend as little as you can; save the difference. You'll have to weigh this against: doing what you love, being social with friends, being comfortable, spending in line with your values (e.g. tithing, charity, sustainable/free-trade). **However**, make it a rule to NEVER spend more than you have in the bank (exceptions: education, mortgage, possibly truly desperate need).
-School: Figure out ahead of time if it will help your career. I wanted to do engineering, so that was a no-brainer, but it might be more complicated for you. Maybe you only need an associates degree to work in your field, or none at all. If you choose to go, optimize costs, keeping in mind that community college and/or state school might not be the best value even if they're the best cost. Some private schools offer great grant aid, so don't be afraid to apply if it looks like you might qualify. Of course look for and apply for scholarships. Try to avoid loans (massive debt!) but if you can't be very aware of how much you are taking on and how you will pay it back.
-Jobs: I feel like some people never hear this: there are more entry-level/student jobs out there than retail and burgers. I've never worked retail or food service; I've been a tutor and a camp counselor which both paid better and gave more satisfaction. My bf's sister made good money and better connections as a babysitter. Bf himself worked as an assistant to a contractor or electrician; got some good skills. Sounds from your username like you might DJ or have an interest in music? If that's true, use that. A high school friend of mine acquired some recording equipment and then offered his recording and editing services to local bands. Another got some gigs as an accompanist around local schools. Don't just focus on one talent, try to think of everything you can do and why someone would pay you for it. Then go sell it.
-Credit: debt, or people lending you money. Open up a credit card to charge to and pay off every month. This builds your credit history (a record of your borrowing and repayment that companies or landlords will use in the future to decide if they want to lend to you, or even judge your overall responsibility). Good history can make life a little easier, bad history can make life hell. More:
http://www.consumer.gov/articles/1009-your-credit-history#!what-it-is -Taxes: Don't be afraid of them, the basics of individual taxes are easy, but be wary if you start a business (look it up/ask for advice).