1. Get a part-time job. This is probably the best way to earn money if you want large sums in a short amount of time. Make sure your resume is brief and informative, and choose wisely on where you apply. If you're wanting the most cash possible, it's good idea to work at a decent restaurant where they divide their tips with the employees apart from your paycheck. Working at a restaurant myself, I once got $40 just in tips for a single shift. Go for the stores that are in interest to you, though! Working can be a fun experience as well if you're expecting to enjoy it. There are often times perks to working at a particular place. If you work in a food place, many places may provide you with a free meal for the shift your working in. Or if you're working in retail, you usually get a discount for the clothes in their stores. 

2. Sign up for a newspaper route. If you're not into all that commitment for a part-time job where hours can be long and your employer asks you to work many days, you can try calling your local newspaper company and ask if there are any available paper routes that you can do. Usually you only have to hand newspapers out about twice a week, and doesn't take too long. You get paid by the number of newspapers you handed out (around 10-15 cents a paper). You probably get paid far less than from a part-time job, and you might have to wake up early for the job, but you get more time in your hands if you're a person that's busy with their academics.

3. Tutor kids in the younger grade. Some schools have tutoring programs where you can sign up to be a tutor to other students who are struggling in a subject, or there are also local programs that you can join. You also have an option to tutor kids that you may know personally through family connections. This is a great way of income because tutoring only takes around an hour, and you can set the price of how much you want to charge for the lessons (usually I'd say $10 to be modest though). Not only will you have a bit of cash coming in, but you should know that parents can right some great reference letters for you!

4. Volunteer! This probably sounds weird to you. What? I can't get any money from volunteering. That's true. Volunteering is where you help out in the community without receiving anything in return. But some volunteer places can offer you a part-time paid position over time, and usually not minimum wage either since you already have the experience through volunteering. This is recommended if you're truly dedicated to volunteering at a particular place and will stick with it for a course of time. Some volunteer opportunities that might employ you over time I know of are day cares and dental clinics (but of course, it doesn't apply to all).

Those are some solid methods to getting that bit of money a teen needs. Some people may recommend joining online sites by doing surveys and polls, but I disagree with those people since you really don't get too much money out of them, and some sites turn out to be scams. It's better to be safe and sorry! While it's nice to get a source of income coming into your little piggy bank, don't forget that school is as equally as important!