The drone terminology and definitions is an online glossary for drone and quadcopter enthusiasts.
Small cameras often sold as key chain cameras.
These cameras are small and light enough to strap onto a quadcopter and take aerial video. These small digital cameras are limited in features but they are very cheap and you can buy one online from around $20 to $50 so they are good if you want to experiment or take video from your quadcopter on a very low budget. The light weight makes them a good choice for using with smaller quadcopters.