These cameras are sometimes known by the brand name "Elmo' (hence the title of this blog post), but the actual item is called a document camera. Kind of like how we call tissue "Kleenex", or call the copy machine the "Xerox" machine...but I digress. A document camera can cost anywhere from $300 upwards; oh yeah, you will need a projector as well, which involves more money, but is very worth it.
Why so worth it? you say....well, basically anything, and I do mean anything, you want to show to your students you can slap up on the Elmo and there it is for the world to see. This could be documents, or math manipulatives, magazine articles, blueprints, cereal boxes, real-world items, or, or, or...be creative. Whatever your math lesson is for the day, you can present it visually. And visual access is one of the keys to providing good math instruction.
Students discussing a math problem using a document camera & projector.
Good luck in your quest....after you get those items we can discuss getting an interactive display board such as an ActivBoard or SmartBoard, but we'll take it slowly...