Well, if you get all the parts, thats the only expensive part. All you need is a video camera, a cable, and a TV.
Take the camera, attach a cable to the video out, and run that to a TV.
The
TD of my school did that last year (put the camera on a tripod on the side of the
house) because he was playing flute in the pit and wanted to be able to see what was happening on stage.
I don't know how much money you have to spend on this, and how permanent you want it, but those are the only 3 things you need.