There are plenty of ways to make money as a teenager here are a few that I have collected, and used, over the years.
With the recession hitting hard many dog owners are working longer and longer hours to try and pay their way, this gives them less and less time to spend with their dogs. For walking their dogs you can earn upto £10 an hour for one dog! If you walk multiple dogs at the same time then you could earn much more. Remember to pick up the dog poo and places it in a bin.
People always need their cars cleaned so you could earn a pretty penny doing this. Charge around £4 a car (make sure you do a good job so you get repeat custom), do 10 cars in a day and you've got yourself £40.
Many people hate to mow their lawns so you could make some money by charging people to mow their lawns, get some flyers printed and deliver them around your local neighbourhood.
Clear out all your unwanted things from your bedroom and from around the house and put them on ebay.
If you live in an area in which there is often snow around, make your extra money by shoveling snow off of peoples driveway. This can make you some decent money as people will pay good money for having their driveways cleared especially if you do a good job.
Cleaning your own and other peoples homes is a good way to make money because, as mentioned before, people are having to spend more time at work, so they have less time to do household chores like cleaning. Offer to hoover, dust, polish and even changing the bedding as part of your service.
The best way to market your business ventures is by creating some leaflets and delivering them in your local neighbourhood. Word of mouth is also a good way to advertise so ask everyone you work for to give you a recomendation to a friend if they think you've done a good job.
Good look and I hope you make some money off of these ideas.