If you have a digital camera and enjoy experimenting with it, you may be interested in selling your digital imagery online. There are a number of sites that allow you to upload images and if they are approved, buyers can pay a small amount to license their usage for their design projects, a portion of which will go to you. Over time (and as you build your library) these small payments can add up. The key is that you have to enjoy working with your camera and learning new techniques because it's not going to be an enormous money-maker, at least not immediately. (You'll need to build a solid library and keep uploading regularly to increase your earnings).