That does sound a bit pricey. I would say they are semi-rare add to that the fact that they are VERY fragile and that explains the high prices. The store is probably trying to make up for the mortality rate of shipping the little finicky things.
Most people I have known that have kept them have liked them a lot but experienced sudden unexplained deaths. They are probably worth a shot if you like them they are not as aggressive as regular JD's so keep them with peaceful tank mates or none at all and keep a close eye on water parameters.