(MONEY Magazine) – You enter the travel agency to book a budget weekend trip, but the agent won't even talk to you until you pay a $20 service charge. When you express vague interest in a South Seas jaunt later in the year, the agent clicks on a TV that plays video cassettes showing half-acre hotel suites and palm-brushed tropical beaches. Now you are told that if you agree to take the $5,000 Pago Pago package, you will get a 10% discount and a half-price flight to the Caribbean next winter. While you're pondering all this, the agent pops up with another proposition: a matched set of Pierre Cardin luggage for only $299. Confused? Exhilarated? Irritated? All of these? Welcome to the hyper new world of travel agents. Behind such wacky permutations is airline deregulation, which has caused fares to tumble, squeezing agents' commissions so severely that revenues often do not cover costs. To remain aloft, many agents have started charging fees for once free services. Others have added new profit centers, hawking products from garment bags to travel irons, to help fatten their scrawny bottom lines. In a reverse tack, a brash new type of discounter has entered the scene, slashing services and rebating commissions to customers. Perhaps the most disappointing effect of deregulation is the sharp deterioration in the amount and quality of travel agent service. Horror stories abound. To plan their $1,000 honeymoon in Mexico last May, Shellie and Jim Nelson of Kansas City, Mo. consulted an agency recommended by Shellie's stepfather. But when Jim, 26, tried to check out at the end of their six-day stay, he was told that the hotel bill had not been prepaid as arranged, and he and his wife would not be permitted to leave Mexico. Frantic, the Nelsons got in touch with their agent, who said he had mailed the hotel payment. To make their afternoon flight, the Nelsons were forced to leave all their luggage and a $1,500 set of golf clubs behind as collateral. Says Shellie, 22: ''We left with the clothes on our backs. It offended me that the agent didn't feel any responsibility once he had our money.'' The agent, who claims he sent the prepayment in time, denies any wrongdoing. To check out the general state of industry service, Money reporters recently shopped 25 travel agencies, pricing air fare and hotel accommodations for an eight-day trip to London (see the table at right). We found an annoying number of uninformed travel agents, a distressing range of prices and frequently slipshod follow-through. At an Ask Mr. Foster branch in Dallas, an agent confessed to not knowing much about leisure travel. His suggestion: return in a week when the leisure specialist would be back. When queried about the best available air fare, an agent at Larchmont Travel in Los Angeles simply handed out a TWA tour book, then quoted a round-trip rate to London at $856, some $200 more than what other local agencies offered. Some agents, when pressed for an inexpensive hotel in a convenient location, refused to make recommendations. Whether the solicitude of your travel firm is Tiffany's or Tijuana, the basics are the same -- air, land and sea bookings. But a crack agent will design a custom itinerary or assemble parts or all of the best pre-arranged tours. A hack agent will go with the first wholesaler he can get through to on the phone or the one who spirited him off on his last junket. In either case, the commissions are 8% to 10% (except for incentive bonuses when airlines are competing for business). These are among the available options: -- Package tours. A wholesaler bundles together flight, hotel and sometimes rental car and sells them through a travel agent at a single all-inclusive price up to 50% less than you would pay for the separate parts. Your travel agent should find out how much you want to spend and the class of hotel you desire and be willing to price packages from competing wholesalers. Since the least expensive tours sometimes include run-down hotels in rotten locations, your agent should screen out such unacceptable accommodations. -- Inclusive tour fares. If existing packages don't suit you, your agent can assemble one for you by booking separate air and hotel reservations. On certain routes, there are inclusive-tour (IT) air fares, on which you save up to 50%. Finding one, though, requires an energetic agent interested in customer service. -- Fly-drive packages. You get the flight and a rental car in one package. This capitalizes on the special contract rates airlines have with some of the major car-rental companies, saving up to 50% on the drive part of the deal. To plump up his commission, an unscrupulous agent might push a more expensive car, so specify the size and class of car you want. -- Charters. Most charter operators book space from an airline and offer fares that are 20% to 40% lower than regularly scheduled flights. A good agent will steer you away from operators with unreliable schedules. The best charters, says Cindy Rubi of Corporate Travel Services in New York City, are those in which the operator buys unsold seats in bulk from regularly scheduled airlines. -- Apex fares. You can save up to 50% on air fare if you buy your ticket at least 21 days in advance. Your agent -- eager to get a larger commission -- may tell you this fare is not available when in fact it is. If you're suspicious, call the airline directly to double-check availability. -- Cruises. A cruise includes meals, stateroom, entertainment and transportation to various ports of call. Your agent should be able to tell you which cruises are geared to your age group and tastes. Experienced travelers, who like to do their own trip planning, are now turning increasingly to a new type of specialist -- the discounter. Usually you choose the hotel but not the airline, and you split the discounter's commissions. One of the biggest of the discounters, McTravel Travel Services (800-331-2941, 312-498-9390 in Illinois), charges fees of $10 to $20 to write air tickets and $25 to $50 for package tours and cruises. The Chicago agency then passes through all of the commissions, ranging from 8% to 20%, to you. (There are no charges or rebates for reserving hotels and rental cars.) Say you're interested in an $857 TWA London Theater Week air-hotel package from New York City. By anteing up McTravel's $25 fee and using its 10% discount, you would pay only $796, a saving of $61. Cashback (800-458-CASH, 212-490-0080 in New York), a Denver-based discounter with an office in Manhattan, rebates up to 5% of its commissions, even on hotels and rental cars. It does not charge a service fee. For travelers who seek a little more assistance, the best prices and service generally come from small neighborhood agencies that want to win your long- term patronage. Large national chains that look for volume business often don't make time for personal attention. Says Richard Kahn, executive editor of Travel Agent magazine: ''A smaller agency may not have all the resources of a larger agency, but the extra touches shape these mom-and-pop outfits.'' The extras include help in applying for a visa or passport, advising on necessary inoculations or health hazards in destination countries and providing you with sound sightseeing advice, theater tickets and reservations at the best nontourist restaurants. Some agencies go still further. Jo Ann Hixon Shell of Exchange Travel in Tampa keeps a file on each customer, listing such minutiae as frequent-flier numbers and airplane seat preferences. When a couple book their honeymoon trip through Edison Travel in Edison, N.J., the agency arranges for a chilled bottle of champagne at their hotel. In fact, such details can make a trip memorable. When Boyd and Jo Ann Evans of Overland Park, Kans. flew to Rome last year, their agent, Erika Nickel of the Travel House, reserved window and aisle seats and the Evanses got an empty middle seat as a bonus. Nickel knew that airlines rarely fill the middle seat unless the plane is full. Out of necessity, though, smaller agencies are cutting back on other frills. When a service doesn't pay, they are now apt to charge for it. Some, like Edison Travel, collect service fees of $25 to write free tickets earned through airline frequent-flier programs; walk-in customers pay $5 for tickets under $100. Personalized Travel Service in Littleton, Colo. charges $10. Says Personalized's Betty Wilcox: ''A lot of things people want us to do are not commissionable. Either we build up a lot of goodwill or we charge a fee.'' Agencies have also gotten into gimmicks. Rosenbluth Travel in Philadelphia screens video cassettes of cruise lines, hotel accommodations and such destinations as Hawaii or Israel to help sell you a trip. Kirby Tours in Detroit has a frequent-flier program that lets you earn coupons you can cash in for gifts like a Japanese tea set or a three-night cruise to the Bahamas. And Burns' World Travel in Statesboro, Ga. sells 100 travel items, including Lark luggage ($80 to $440) and currency converters ($21). But how do you find that peerless paragon who will get you the lowest air fare, the right hotel and savvy extra help? The obvious way -- by asking friends and co-workers for recommendations -- still works, but not always, as the honeymooning Nelsons learned. It's best to do some screening of your own. Industry observers advise you to deal only with agents that have been in business for at least five years. Here are some basic questions to test a travel firm: -- What kind of research will you provide? An agent who gladly prepares a | sightseeing itinerary in Hong Kong or a driving route through the south of France will likely perform other chores well. -- Has anyone in the agency been to this destination? An agent who has actually visited an area is far better prepared to give you expert advice on subjects like accommodations, seasonal differences and cultural activities. -- Can you update me on the service performance of the airlines? Since deregulation, there has been an increase in complaints about delays, cancellations, lost luggage and other failings, particularly at the discount airlines. -- Are you willing to ferret out the lowest air fares? The International Airline Passengers Association gets some 300 complaints a month, many of them about prices. The reduced commissions on cheap fares provide little incentive to do the necessary digging, though the majority of agents are equipped to find discount flights without difficulty. Most agencies are computerized and use one of the five reservation systems, which list all flights by departure times. A lazy agent may stop at the first computer display, but one worthy of your business routinely scrolls down several screens to find bargains. With the average fare changing every two weeks, however, even the most competent agent may feel besieged. You can backstop a questionable agent, suggests Roger Scott, assistant editor of the magazine Best Fares, by predetermining which airlines fly to your destination and asking their fares. ''It's a good check and balance,'' he says. In the search for low fares, ask your agent to dig for so-called hidden cities. To meet the competition, carriers sometimes offer a lower fare to a distant destination than to a nearer connecting city. By booking your flight to the less expensive city and deplaning when you arrive at the connecting city, you can often cut your fare in half, says Scott. For this to work, you should, of course, carry your baggage on the plane.

If your agent can't obtain a discount, ask to be put on a wait list. According to Scott, most airlines have at least two grades of wait lists -- regular for customers booking directly and priority for reservations made by travel agents. Sometimes agents can ask the airlines to open up additional cut-rate seats and then can also find out exactly where you are on a wait list. Adds Scott: ''You'll probably have to prod your travel agent to perform this kind of service, but if he's agreeable, you know you've found a gem.''

BOX: Shop around, voyager Money reporters visited 25 travel agencies in five cities to price an eight- day trip to London departing May 2, 1987. We asked for the lowest available round-trip air fare and a moderately priced room with bath. Costs are for one person based on double occupancy. The table includes each city's high and low quotes.

Air fare Hotel Total Comments DALLAS Encore Travel $822 Included $822 Package includes round-trip in air fare transfers between airport and city, Continental breakfast, half-day sightseeing tour.

Ask Mr. Foster 711 $306 1,017 Nothing included.

KANSAS CITY Travel House 630 120 750 By booking air fare through TWA, travel agent saves two- thirds on hotel room

American 630 379 1,009 Half-day of sightseeing Express included.

LOS ANGELES 9 to 5 Travel 571 159 730 Half-day of sightseeing included.

Ask Mr. Foster 699 432 1,131 Includes Continental breakfast.

NEW YORK CITY Corporate Travel 408 289 697 Transfers, Continental Services breakfast included in packages.

American 706 345 1,051 Transfers, Continental break- Express fast, half-day of sightseeing, two theater tickets included in packages. TAMPA Downtown 562 169 731 Charter from Orlando; includes Travel transfers, Continental breakfast, walking tour.

American 681 399 1,080 Half-day of sightseeing Express included.