Well you can always be a vendor rep in retail stores. While stores like Best Buy and Circuit City often hire 16 and up, individual vendors hire store Reps who are college students and some graduates. In fact you have to be 18 sometimes 21 and over to qualify for a position with many of these companies.
Vendor Retail Rep jobs like for Epson (Mosaic Sales), SBC Yahoo DSL (Mosaic Sales), HP (MarketSource LLC), or Lexmark (not sure the marketing company in charge) pay between $14-$17 an hour and are usually only weekends (Friday sometimes, but usually Sat & Sunday) for about 10-15 hours per weekend.
So its good money for what you do, not a lot of work, and you get to visit all kinds of stores (usually Reps get assigned to different stores all the time, so you meet and get to know the managers of many retail stores) which usually helps you build connections and get hooked up with awesome deals.
Here are some links to the companies that run these programs:
www.mosaic.com
www.marketsource.net