Calculator prices for insurance

Does anyone know of any online resources containing rough prices for mechanical and early electronic calculators? I need to sort out some insurance details for some of the museum collection, and whilst I can come up with ballpark figures for the big iron and ebay's a good source for prices for common 8 bitters, it doesn't help for some of the early (and rare) mechanical / electronic calculators. Are there any good online resources out there, even if prices are a little out of date? (In particular I'd like to put a value on some of our Sumlock and Anita stuff) Out of interest, my general insurance thoughts are: The insurance value should really cover the costs of finding something of similar "value" in the event of a lost item being unobtainable. So it needs to cover purchase cost, shipping cost, additional purchase of any manuals/docs/software as necessary, and of someone's time to commission the item and learn how it works. In other words, it's more than the simple "but it on ebay" value. Thoughts, anyone? cheers Jules -- "We've had a lot of loonies around this place, but you're the first one who thought the sunrise was made out of stale beer. Now are you going to pick up your flute and leave, or shall I part your hair with this crowbar?"