You can get him a game present of word of warcraft since teens at this Age love games a lot, you can also buy him an apple iPod shuffle. Other gifts you can choose from are cell phones, cologne, a watch, new clothes, a digital camera or a laptop.
Look in his room..what is most dominating his place? What is his hobbies and/or interests? If you know your brother well, than you should find something in your price range that may be perfect to his taste.