This seems to be an out-of-print book or product, which is apparently hard enough to find that the people who want to sell their used copies, and the retailers who happen to have (supposedly) new copies to sell, feel that they can get away with charging outrageously high prices for it. This doesn't mean it's worth the asking price-- and the fact that the book or whatever-it-is has not been kept in print (and also that "new" copies of it seem to still be available) might suggest that it wasn't exactly flying off the shelves due to high demand. In other words, purchase with caution-- and, if possible, only after holding it in your hands and leafing through it to see if it looks worthy of the asking price.