Cabins are priced based on location on the ship. Typically cabins on lower decks are less expensive. Typically cabins midship (in the middle part of a deck) cost higher. Balcony and Suite cabins on the very aft of the ship can also be more expensive than other cabins.
Inside cabins: These cabins are usually the lowest price. Typically they will have twin beds that convert to a queen size, a private bath with a shower, a closet for hanging clothes, a dresser and a television. These cabins do not have a window to let natural light in. To help give the occupants an impression of having a view, some inside cabins have a virtual view. That means there is a large screen that displays outside views. Expect to pay $100 to $200 a night for an inside cabin.
Exception: Royal Caribbean and other cruise lines will also use sub categories to distinquish between how many occupants the cabin will sleep. Therefore a cabin that can sleep up to 4 people will be a different sub category from a cabin that sleeps only 2 people.
Since cruising has become a popular family vacation, more new ships have built "family accommodations" into the actual design. These are often suites, each with a separate room for the kids -- sometimes a small alcove with bunk beds, sometimes an entire adjoining cabin. Families and groups can also take advantage of regular staterooms with third or fourth berths found in pullout sofas or pull-down bunk beds (called Pullmans). If you are going to squeeze your whole troupe into one cabin, make sure the space is big enough to accommodate the lot of you ... and all your belongings.
carnival cruise interior rooms
carnival cruise room layout
cruise ships with 2 bedroom suites