As a young adult myself I can vouch for the fact that saving money every week, or even every month can be a bit of a hassle especially when their are always new gadgets to buy, and movies to go see. However with the current economic situation it may be in the best interest of everyone, especially teenagers to start investing their money into some sort of investment vehicle.
The most common investment vehicles that we see today in America come in the form of stocks and mutual funds. These are essentially the same product in that both give you ownership to the company you purchased them from, the only difference lies within the fact that with a mutual fund your risk is more spread out amongst different options and with stocks you have all your eggs in one basket so to speak.
In any event, once you have decided which form of investment you will make, you must decide on which company to invest in. The reality of it is, the stock market has shown us one thing over time and that is growth. Even through periods of recession and depression the long haul has brought an increase in the American economy. With that in mind you should look for a large cap company which holds the lowest risk, and begin to make small weekly investments. Investing money in this manner will allow you to have a nice nest egg setup for whatever the future may hold for you, things such as weddings, mortgage payments etc. can all be set up and paid for from your weekly deposit that you started making in high school.
At the end of the day it may not be the cool thing to do amongst your friends, but rest assured that when college graduation rolls around and you have money waiting for you it will make things much easier for you and your family.