How cheap do you need?
ZWO makes a range of very affordable astro-cameras
http://astronomy-imaging-camera.com/products/usb2-0/ - they can take a standard CCTV lens, and the one I bought (ASI 120 MC) came supplied with a 2.1 mm fish-eye lens which gives a 150-degree sky view. It has plenty of sensitivity for doing real-time night-time video or time-lapse photography with the fish-eye lens installed, pointing straight up.
I also have a longer focal-length CCTV zoom lens for more conventional sky views, and of course it also fits into an eyepiece holder or T2 thread for prime focus photography, or it can be used as a guide scope.
All in all - a very capable piece of kit, for not much money!