Berlin isn't actually a cruise port, but is served by the ports of Warnemunde and Rostock. In total, Warnemunde and Rostock is the port of departure for only thirty sailings every year from MSC to Europe.
Overall Berlin is rather inexpensive compared to other ports. The diagram below shows the monthly average cost per day for cruises from Berlin (Cruises only depart from Berlin between May and September). Sailings scheduled from Berlin during the peak seasons of spring and summer are significantly more expensive than the the low season of fall.