I was wondering if you have a price limit on how much you would spend on a cruise per day? For me it varies depending on the type of cruise. For a river cruise it would be higher because shore excursions are included. My paddle steamboat cruise costs more per day than my mega cruise ship cruises do, also. I don't have any hard and fast rules for this. I have never taken any of the luxury cruise ships yet and probably never will unless a great deal comes along.