The SBD price on coinmarketcap comes from the average price of SBD over the top five exchanges,hitbtc being one of them,i heard that the price on there was $50 dollars! There prices are usually higher due to low volume.basically the figures on coinmarketcap are not a true reflection of the SBD price.
I use coinlib.io,it gives a more accurate price and there are no ads.i hope this helps a little bit.