Cost

For one price, a cruise gives you all your meals, accommodations, and onboard entertainment. The only extras are tips, shore excursions, shopping, bar bills, and other incidentals. However, the axiom "the more you pay, the more you get" doesn't always hold true: While higher fares do prevail for better ships, which have more comfortable cabins, more attractive decor, and better service, the passenger in the least-expensive inside cabin eats the same food, sees the same shows, and shares the same amenities as one paying more than $1,000 per day for the top suite on any given ship. (A notable exception is aboard the Queen Elizabeth 2, where your dining-room assignment is based on your cabin category.)

A handy way to compare costs of different cruises is to look at the per diem -- the price of a cruise on a daily basis per passenger, based on double occupancy. (For instance, the per diem is $100 for a seven-day cruise that costs $700 per person when two people share the same cabin.)

Of course, there will be additional expenses beyond your basic cruise fare. When you go to book a cruise, don't forget to consider airfare, transportation to the ship, tips, shore excursions, and other incidentals.