I'd price the pipes new, and used on ebay, and see if there are any at online retailers like SP or PC, to give you a range on these. With estates, so much depends on the condition of the pipes. You might even discuss this with the Blatter & Blatter people themselves. The more you know, the better shape you'll be in to counter offer. That many pipes at that price suggests you are buying for more than just the pleasure of owning or smoking them, so have clearly in mind what you expect. They are custom made, which justifies a higher price, but the asking price seems pretty high, not having seen the pipes.