The average daily price for Caribbean itineraries varies dramatically depending on several circumstances. The cost of a cruise on a luxury line such as Silversea or Seabourn may be three or more times the cost of a cruise on a mainstream line such as Carnival or even premium lines like Holland America. When you sail will also affect your costs: published brochure rates are usually highest during the peak summer season and holidays. The length of your cruise and the type of line are the two biggest factors in determining the cost.