I know this is a little late, but around $300 (SPD, or £100uk). That should get you all the acessories supplied with the camera when new.
Best thing to to is to go to an auction site such as e**y (you know who I mean) and search completed auctions for what you are looking for. Don't forget to check any postage costs when checking.
Such sites are a useful way of finding out what people are actually willing to pay, and as with all things, that's what the 'true price' really is.
Also check what the camera would have been supplied with as new. If any are missing reduce the price by the cost of new replacements, as these are often difficult to obtain second hand.