Bangkok is served by the port of Laem Chabang, but isn't itself a cruise port. Together, the port of Laem Chabang functions as the point of embarkation for only one sailings per year from Norwegian to Asia.
On average cruises from Bangkok are moderately expensive compared to other ports. Check out the chart below for the monthly average cost per day (Cruises only depart from Bangkok between January and February). Prices are about steady throughout the year.