If you are 14-15 years old you may be able to work, but there are many limits, you can work in retail occupations, intellectual or creative work, errands or deliveries, cleaning up/ yard work, work with cars, food service, cleaning food, unloading/loading objects. Some teens may even be able to work in wood shops and sawmills, or be a lifeguard. Fourteen and Fifteen year olds have to work outside of school hours and may not work three hours on a school day or more than 18 hours a school week. You would not be able to work more than eight hours a day when there is no school in session.
If you are 16-17 the options are more broad and there is a greater chance of getting a job, or at least a well paying job. You will be able to work unlimited hours and you may work at any job that has not been called hazardous by Secretary of Labor.
There is also no limit on the number of hours that you can work when you are 18. Although you may work at any job that you wish to work at. There is no limit on the jobs you can work for and the hours you wish to work.