What is the cheapest digital camera you can buy and how good could it be?
The cheapest camera I could find is a 100k Pixel (0.1 megapixels, 352 x 288) digital camera sold under several brands including the Philips Key chain Digital Camera Item model number: P44417S, Philips USA J44417 Keychain Digital Camera, VUPOINT DC-M10B2-VP Key chain Digital Camera, Bell+Howell Mini Digital Camera, Innovage Outdoor Sports Mini Digital Camera Model 1507651 and Q-See QS513K VGA Mini Digital Camera with Keychain.
The camera comes with 2MB of dynamic ram that is able to take 20 pictures. Because the memory is dynamic rather than static, unlike more expensive cameras if the battery dies you will loose all your pictures. The camera is very small, 2.4" x 1.6" x 0.7" and only 2.4oz without the battery. The camera is also able to function as a web cam. The camera is under $15 and can be found for under $10.
How good could the pictures the camera takes be? Better than I expected but the camera is only $15 so, you will never get the same level of quality you would with a real camera. As with most cheaper cameras if you plan to actually use this camera it must be done in bright sunlight or the photos will come out dark. You must also have a very steady hand and have a still object to photograph because there is a delay from when you hit the exposure button and when the camera takes the picture. So it is possible to buy a camera for under $15 but I would consider the camera more of a toy or novelty than a practical camera.
The pictures below were taken using the Philips model: P44417S.
As a web cam the camera does function significantly better than expected. If you are looking for a very cheap webcam it does function quite well. While in web cam mode it still uses the battery versus the USB connection for power but it can get a couple of hours out of the battery using the camera as a web cam.