Does anybody pay full fare on a cruise these days?

Almost every cruise ad, it seems, is offering big discounts on voyages to sun-splashed island ports. Book now and "save a generous $1,000" per cabin, touted a prestigious cruise line a few days ago. And travel agents and discount firms specializing in sea vacations are putting together their own cut-rate deals.

As a result, a substantial number of passengers manage to snap up a cruise at considerably less than the price published in the cruise line's official brochure. A wise traveler, willing to shop around a bit, can do the same. But it is important to note that some bargains aren't always the value they appear to be.

As many as half the passengers sailing today get some kind of discount, estimates Richard White of White Travel Service in West Hartford, Conn. His firm, now in its 20th year, specializes in reduced-price cruises. The fact that the other 50 percent are paying full price, he says, "shocks me. It means I'm not getting the word out."

"In the years I've been in the business, I've had only one client who paid full brochure price," says five-year veteran Jennifer Felt of Cruise Time, a Fairfax City cruise-only travel agency. "I felt so guilty, I paid the limo fare to the ship."

"There are so many special offers out there right now," says Fran Sevcik, a spokeswoman for Norwegian Cruise Line, which features Caribbean cruises out of Miami and San Juan. "If consumers are smart, they would shop around."

So how do savvy passengers find the bargains?

Obviously, the discounts are available because the cruise lines have empty cabins they can't sell any other way. Three major factors are cited:

The American economy is weak, and a cruise may seem an extravagance to someone on a tight budget. In addition, many people have become very uneasy about foreign travel since Iraq invaded Kuwait five months ago, and the U.S. attack on Iraq has heightened those fears. This double whammy has come at a time when the cruise lines have just introduced more than a dozen new ships, including huge super-liners carrying more than 2,000 passengers. There are a lot of extra cabins to fill.

"In the current marketplace," says Ron Bitting, president of the National Association of Cruise Only Agencies, "every cruise line and every cruise {travel} agency is using discounts as a marketing tool." Bitting heads Personal Touch Cruise Consultants of Freeport, N.Y., one of the association's 800 cruise agencies. Virtually all the cruise lines, even the pricey ones, offer regular discounts or special promotions of one kind or another.

How the cruise line industry is organized also plays a part in discounting. None of the major cruise lines routinely takes cabin bookings directly from passengers. Instead, they deal almost exclusively through travel agents, some of whom claim to be able to negotiate much better deals for their clients than others can.

The cruise specialists -- White, Felt and Bitting -- say the cruise lines make discounts available in a variety of ways. Among them:

Advertised discounts: A large number of cruise lines advertise reduced rates directly to the consumer. The most common discount is for early bookings, although special promotions are apt to be offered when business is slow, as it is currently. Princess Cruises, for example, is promoting a $500 "Love Boat Saver" discount per cabin on fall sailings to South America, available to anyone making a deposit before July 4. Early booking discounts generally range from 5 to 20 percent off the brochure price.

The cruise lines solicit early bookings, says Bitting, as a way to determine how many airline seats they will need for passengers flying to the departure point. Many cruise lines include round-trip air fare in the price of a cabin. A consumer can go to any travel agency to obtain a cruise line's advertised discount.

Among recent promotions, the Cunard Line is offering a low "standby" fare for transatlantic sailings of the QE2 -- you are told the departure date only four weeks in advance -- and Carnival Cruise Lines is offering a discount of $400 per cabin on cruises to the Bahamas through March 24.

Group rates: A group of 16 or more people traveling together can usually obtain a discounted rate negotiated by a travel agency. Typical groups are church and school organizations, sports teams, garden clubs and professional associations.

Better rates for favored agencies: A travel agency bringing in a good volume of business can usually get better rates from the cruise lines it uses. According to Felt, the cruise line may allow the agency to offer the group rate to couples traveling independently. Even a better discount is the "flat rate special." As Felt explains it, a cruise line will quote a low rate to favored travel agents and allow the agents to book all their clients at that price. The clients will then get an upgrade into the best available cabin.

"We have preferred suppliers who give us better deals," says Felt. "I get weekly faxes from the larger cruise lines. I have a three-inch notebook of them I have to go through daily." Usually, the cruise line prohibits her from advertising the discount publicly, but she can provide details to customers.

Sometimes she will call up a cruise line and ask, "What can you offer me?" Good travel agents, she says, "hustle for their clients."

Norwegian Cruise Line is one company -- maybe the only one -- that has made it a policy to advertise all its discounts and special promotions publicly rather than limiting some offers to favored agents. "We don't believe in playing favorites with discounts," says Doug Falk, vice president for marketing and sales. High-producing travel agents are rewarded instead with higher commissions.

Purchased space: Larger travel agencies, such as White's, may be able to book blocks of cabins in advance at lower rates and pass the savings along to clients. "I've got space guaranteed as far ahead as 1993," White says.

Last-minute sales: Prices plummet on some cruise lines as the ships get ready to sail. A cruise line may make last-minute prices available to a cruise discounter, such as The Cruise Line of Miami, a travel agency specializing in last-minute bargains. Or it may advertise them to the general public. Norwegian Cruise Line regularly offers what it calls a "sea saver" price for passengers who book less than 30 days before departure.

One major drawback to last-minute bookings, however, is that air fare to the departure port probably won't be included in the price. If you can't find a low air fare, a cheap rate for a cabin may not be much of a bargain after all. And, of course, at the last minute you generally can expect to get only what's left over in cabin selection. Some of the more prestigious cruise lines reportedly never offer last-minute deals.

Other variables, such as a ship's popularity, the season and the destination, have an impact on the availability of cruise discounts.

Travelers should realize that the best ships often fill up, especially to popular destinations such as Alaska. As a result, discounts may be limited, and you may be out of luck if you wait to book. Despite the economy, "an awful lot of ships are going out full or wait-listed," says White -- "the upscale, ultra-deluxe ships in particular. The people who choose them are less sensitive to changes in the economy."

The cheapest cabins also go early to budget-conscious passengers, and "quad" cabins that can accommodate a family of four can be hard to get at the last minute, especially during school vacation times.

Alaska is the destination that tends to sell out first, say the cruise experts, because the trip is very popular and the season is short. Most of the cruise lines plying the Inside Passage offer early booking discounts. Whether additional discounts become available depends on how bookings shape up in the weeks ahead. Some bargains may be offered for end-of-season sailings in late summer.

Right now, plenty of bargains are to be had for Mediterranean cruises this summer. Bookings are said to be very slow because of the Middle East crisis. Discounts also are readily available on cruises to South America -- where two passengers can sail for the price of one, says Felt -- and the South Pacific. In the Caribbean, which is a year-round destination, the best deals are in the fall or the two weeks just before Christmas. Of course, fall is the hurricane season, which makes it a less appealing time to sail.

Given the nature of cruise discounts, travelers might develop a strategy for booking a cruise based on how flexible their vacation plans are. "You need a high degree of flexibility," says Bitting, "to take advantage of the best deals."

Least flexible: Passengers who must travel during a specified vacation period may feel more comfortable in booking as early as possible. They will have first choice on such amenities as early or late dining, a double bed or twins and the best cabin location and configuration in their price category. Any travel agent should be able to provide information about an early booking discount on the cruise of your choice.

Somewhat flexible: If you are willing to wait a while -- until perhaps 90 to 120 days before sailing time -- you should be able to find a good price on the cruise that you want from a cruise-only travel agent, or a general travel agent who does a lot of cruise business. Alert the agent that you are looking for a good deal, since some are snapped up overnight. Meanwhile, keep an eye out for special promotions in the travel section of your Sunday newspaper. To get the best deal, you should shop around among agents. Remember, however, that your choices are fewer the longer you wait. "A bargain isn't a bargain," warns White, "unless you get something you would want at full price."

Very flexible: When price is most important, and it really doesn't matter much what cabin you get or where the ship is headed, you may prefer doing business with a last-minute discounter. They often advertise in Sunday newspaper travel sections. Here, too, shopping the discounters is advised. Because getting a cheap air fare at the last minute may be difficult, often the only travelers who really benefit from a last-minute fare are the ones who can drive to the port. However, if you keep trying, you may get lucky and find a cheap, last-minute cruise with air included.

A list of local cruise-only travel agencies can be obtained by sending a stamped, self-addressed envelope to the National Association of Cruise Only Agencies, P.O. Box 7209, Freeport, N.Y. 11520. Request agencies in no more than three states.

For more information from the agencies mentioned above:

Personal Touch Cruise Consultants, Freeport, N.Y., 800- 477-4441 or 516-378-8006.

White Travel Service, West Hartford, Conn., 800-547-4790 or 203-233-2648.

Cruise Time, Fairfax City, 703-641-4977 or 800-627-6131.

The Cruise Line, Miami, 800-777-0707 or 305-372-2830.