Costs vary quite a bit based on cruiseline, destination, length of cruise and type of cabin. About 15 years ago, I went on a 3 day cruise to Ensenada that cost $300!
I think we should throw Nuts on a cruise ship and sink it.
They are really good for relaxation purposes. They have a lot of activities on cruises, so you can do things if you want to, but you certainly don't have to. And you can still take other vacations where you go immerse yourself in different cultures. It doesn't have to be an either/or thing.