There are quite a few differences between blackberries and black raspberries, starting with the fact that blackberries are a much better source of fiber than black raspberries. Blackberries also come off the cane whole, as opposed to black raspberries where this is not the case.
Black raspberries leave a car which resembles red and yellow raspberries. As far as the cost of these berries are concerned, black raspberries tend to cost quite a bit more than regular blackberries. On average black raspberries cost a dollar per quart more and are generally more in-demand than blackberries when it comes to shopping at the supermarket.