A camera is a device that captures light and digitally turns the captured light into images that can be transferred to your computer. This tag applies to digital handheld cameras; use the "webcam" tag for a webcam instead.
Cameras can be found as a commonplace household item and be seen in public frequently. Prices for cameras range anywhere from ten to thousands of dollars. For more details on the technical aspects of cameras, take a look at http://www.howstuffworks.com/camera.htm.