I paid £60 in a shop for mine - and that was in the days before the internet.
However with a little ingenuity, and from the results of that ebay search:
case £6 + postage
internals £10 + postage
base £3 + postage
leaving our intrepid collector to hunt down a handset, dial, and drawer front (the drawer front being the expensive bit, and £20 from another ebay seller)