TRAVEL INSIDER : Solo Globetrotters Find Strength in Numbers : Singles: Various organizations are offering ways to beat the high cost of touring alone.

Here’s a tender Valentine’s Day message for all the single travelers out there: Yes, you have been getting a bad deal for years, and no, that’s not likely to change anytime soon.

On cruises and tours, partnerless travelers routinely pay 20%-50% above the per-person rates of couples. In U.S. hotels, singles often pay twice as much per person as couples do. And then there’s the social side of the equation.

“You can really feel like a fifth wheel if you get placed in a dining room with a table of all couples,” says Wendy Lowenstein, manager for Singleworld Cruises and Tours in Rye, N.Y. “You wonder, what and I going to do, and who am I going to do it with?”

It’s true that some cruise lines and tour companies pledge to find roommates for singles, or hold down the “single supplement” charge when one person occupies a room meant for two. But the bottom line is that as long as people tend to travel in couples, the travel industry is likely to build hotel rooms, cruiseship cabins and prices around that expectation.

The best way around those circumstances may be to draw bargaining strength through one of the many organizations now devoted to the care and feeding (and sometimes, it must be said, mating) of the lone traveler.

Some of these organizations specialize in the young, some in the mature. (Many “single” travelers are women whose husbands prefer to stay home.) Some arrange for you to share space with a stranger; others leave you in solitude but put you in line for a discount. Most are tour operators, but there’s also a newsletter and a cruise “hotline” listed. An unscientific sampling:

For the young and flexible. Contiki Holidays (1432 E. Katella Ave., Anaheim 92805; telephone 800- 466-0610 or 714-937-0611) is a 32-year-old company founded to serve young New Zealanders traveling in Europe. Contiki specializes in budget trips for travelers aged 18-35, and 60% of the customers it books are signed on as singles. Average age: 24. Most customers are Australian and New Zealanders, but the firm estimates that it sent almost 10,000 Americans abroad on tours last year. “They don’t have a lot of money,” says Contiki president Jerri Ross. But at that age, many travelers don’t mind sharing rooms with up to three strangers. As with most companies that try to match lone travelers, the company’s only screening category for same-sex roommates is whether they smoke. Sample trip: An upcoming 11-day trip to Egypt, including Cairo, Aswan, Luxor, and a two-night Nile cruise: $655 (airfares excluded), if you share a room; $870 for a single room.

For the older and wiser. Elderhostel Inc. (P.O. Box 1959, Dept. NM, Wakefield, Mass. 01880-5959; tel. 617-426-7788, requests by mail preferred) is a 19-year-old nonprofit organization that operates as a clearinghouse for 1,800 educational and cultural programs worldwide, often lodging participants in college dormitories. The programs are open to travelers age 60 and older, and last year drew an estimated 250,000 participants (among them many repeat customers). “About 35% of our participants come alone. And 67% of our participants are women. You are immediately welcomed as part of the group. You are not regarded as a solo traveler,” says Cady Goldfield, Elderhostel’s director of public relations. Travelers who want single rooms pay a single supplement, which varies by host organization. Sample trip: April 4-10, single participants share twin-bed dormitory rooms (bathroom down the hall) at Southern Oregon State College in Ashland, taking three no-homework courses (Shakespearean women, music of social change and a behind-the-scenes look at the Oregon Shakespeare Festival). The fee of $320 excludes air fare, but includes meals and various admission fees and field trips.

For the bold and companionable. Jens Jurgen, divorced and experienced in the travel business, started Travel Companion Exchange Inc. (P.O. Box 833, Amityville, N.Y. 11701; tel. 516-454-0880) in 1982,drawing on a mailing list bought from a singles club. The Travel Companions newsletter, published six times a year, runs 30-34 pages and is divided between traveling tips and listings of individual travelers seeking companions. (A six-month membership, which includes listings in the newsletter, runs $36-$66. A six-month newsletter subscription alone runs $24.) Most newsletter readers are over 30, and Jurgen says he makes “a huge effort, constantly, to find more men.” Clearly, some voyagers are hoping for rather close companionship; many listings include the traveler’s age, height and weight.

By sea, by land. Singleworld Cruises and Tours (P.O. Box 1999, Rye, N.Y. 10580; tel. 800-223-6490 or fax 914-967-7395) started arranging modest land tours 36 years ago, but has evolved into a singles-only tour operator serving about 15,000 customers a year. Three-fourths of those travelers take cruises, booked through Carnival, Norwegian and Royal Caribbean cruise lines, with up to four travelers sharing a cabin. Singleworld land packages cover Europe, Israel and Egypt, pairing travelers in rooms with twin beds. Most, says manager Wendy Lowenstein, are 25-45 years old, though the company will serve anyone over 21. Sample trip: On a seven-day cruise to the Caribbean this June, including round-trip airfare between Los Angeles and Miami, Singleword offers bunk-bed berths in a four-person cabin for $995 each. For 10-day tours of Israel (airfares excluded) in May and October, Singleworld’s price for room-sharing travelers is $865.

By sea, by phone. Callers to “Sea Singles” at (800) 777-0707, extension 613, hear a recorded introduction, leave their name and traveling particulars, and in return get cruise information. The Cruise Line Inc., a 10-year-old Miami travel agency and purveyor of discount cruise opportunities, set up the hotline in February, 1992. From the beginning, the service has offered to match travelers by gender, age and smoking habits, but vice president for public relations Donald Lansky says most of the year’s estimated 800 solo travelers haven’t been interested in sharing cabins. More often, callers use the “Sea Singles” line to find berths at discounted rates, which the company gets by pre-purchasing blocks of cabins.

For the restless. Travelin’ Singles (P.O. Box 111, Artesia 90702- 0111; tel. 800-748-6662 or 310-924- 6662). President John La Point, an alumnus of Parents Without Partners, started Travelin’ Singles 13 years ago. He organizes about a dozen trips a year and circulates five or six mailings a year, summarizing past trips, pitching future offerings, aiming “to fulfill the needs of restless singles.” Last year, groups visited New Orleans, Calgary, Turkey, Indonesia and elsewhere. La Point, who runs the business with partner Margie Kerr out of his home, estimates that he served 500 travelers or more last year. Members (La Point counts about 1,000) pay $15 a year to receive mailings, but get a modest price break if they take a trip. Sample trip: This weekend, La Point expects to be in Cabo San Lucas with 48 customers, each paying $380 for round-trip air fare, three nights’ lodging and a first-night cocktail party.

By bicycle. Backroads Bicycle Touring (1516 Fifth St., Suite Q430, Berkeley 94710-1713; tel. 800-245- 3874), founded in 1979, began offering only bicycle trips but has diversified to include walking, cross-country skiing and student trips reaching 69 destinations and serving about 8,000 travelers last year. In 1989, the company started offering singles bicycle trips to travelers of all ages. Backroads’ schedule includes singles trips to 27 destinations in North America and Europe. Trips last three to nine days; they include six to 26 travelers and one or two group leaders, with a support van, accommodations and meals. Sample trips: $188 for two nights of camping, meals and riding in Sonoma County; $2,788 (airfares excluded) for a nine-day bicycling trip through France’s Loire Valley, with all meals and accommodations in country homes and castles included. If travelers sign up early enough, the company will guarantee that it will find a roommate. Backroads usually assembles rosters with no more than 60% of one gender; “leftover” singles who sign up too late are placed on waiting lists for later trips.

Sharing quarters. Mayflower Tours (1225 Warren Ave., Downers Grove, Ill. 60515; tel. 800- 323-7604) is a 14-year-old tour operator that runs trips to Europe, Mexico and North America. Cosmos Tourama (5301 S. Federal Circle, Littleton, Colo. 80123; tel. 800-851-0728), a 32-year-old operator of budget tours, runs trips to Europe (about 50 a year), North America and the South Pacific. Both companies serve a broad clientele that includes about one-third single travelers, and both appeal to singles by guaranteeing that they will match up roommates among travelers who reserve well in advance. If the companies can’t find someone to share your room, they absorb the extra cost.