It might have cost $200 new, but nobody's charging $200 for them anywhere now because they aren't being made any longer. Looking at what they're going for on eBay and Reverb (when you can find them), $550 isn't an exorbitant price. But that doesn't mean I wouldn't make a lower offer if I was interested. It's fair, unfortunately. But if you want it, offer him $500. Or offer him $450 and point out that handing it to you means he doesn't have to ship it anywhere.