What goes on with binocular prices?

I've been looking at a new pair of binoculars for astro use but I'm getting lost - the prices seem to be all over the place. If you take a fairly average spec - say 8x42 or thereabouts - then prices seem to vary from under �50 to well over �1000. How can such a price difference possibly be justified? Surely this is a simple case of some people being gullible enough to buy anything?