Do you have to have a whirlpool bathtub or a walk-in closet? Will you be entertaining and thus in need of a dining table that can seat six or eight? Do you want benefits like priority dinner reservations and being first in line to get on or off the ship? Do you want to be pampered with extra-plush linens and bathrobes, fancy bath products and in-suite coffee and booze? You can find those amenities and more in most of the upper-level suites.
When trying to determine how much cabin you can afford, do not forget to factor in the cost of the rest of your trip. If you have to spend a lot on airfare, pre-cruise hotels and activities in port, you might not be able to afford the fanciest suite; if you are using frequent-flyer miles or do not need to book a hotel, you will have more money for cruise fare; the money you save on airfare can be used to spring for a nice stateroom. Or, look for value-added perks from cruise-line and travel-agent promotions. Offers for complimentary onboard cash, prepaid tips or included airfare can free up some money to pay for other vacation expenses.
In order to set the pricing many cruise lines will divide each cabin type into sub categories. For example a balcony cabin may be divided into sub categories such as B1, B2, B3, B4. In most cases the cabin size and features in a sub category is the exactly the same. The only difference is usually the location of the cabin on the ship. Please look for the notes on the category descriptions to determine if there is a difference in size or features between the subcategories.
Pay attention to the unique cabin setups on your ship, as they are not all created equal. Disneys four cruise ships, for example, have large standard staterooms designed to accommodate families. Even inside cabins may have a sleeping section that can be curtained off from the living area along with a split bath system. (One bathroom has the shower/tub and sink, another a toilet and sink.) Carnival is also known for having larger-than-average standard cabins, while Silversea, Regent Seven Seas Cruises and Seabourn ships feature all-suite accommodations. Norwegian Epic cabins sport the "new wave" design, with curvy walls and separate rooms for showers and toilets; sinks are located in the main cabins. As mentioned earlier, cabins at the very front and back of a ship often have different layouts than the cookie-cutter cabins that run the length of the ship.