If you are no longer a student but not yet a senior citizen, you might occasionally grumble that discounts seldom come your way.

Businessman Martin Shafron overheard one such complaint about a year ago and vowed to do something about it. He retaliated by founding the American Association of Young People, which provides travel benefits plus health, financial and legal services to that vast group of us who are too old for cutoffs but too young for cardigans.Annual dues are $20 and members (the target age group is 18 to 50) can count on paying 5 percent less than an airline's lowest advertised price, Shafron says. (For information about American Association of Young People travel benefits, call (800) 843-6721.)

If you like the idea of saving 5 percent, you will no doubt love the prospect of saving 10 times that amount. For membership fees of about $30 to $100 a year, a handful of travel clubs offer members 50 percent off hotel rates plus selected other travel bonuses. There is usually a mix of upscale and mid-priced hotels.

Qualifiers such as "subject to availability" are rampant but clubs seem to be upfront about their limitations. Staffers usually volunteered the fact that participating hotels stop offering discounts when room-occupancy reaches a predetermined capacity level, typically 80 percent. They did not add, however, that therefore it is risky for a traveling family to count on spur-of-the-moment windfalls.

Clubs either issue a coupon booklet or an ID card and a directory of participating hotels (the more lodgings listed, the better your chances of finding a 50 percent discount at a time and place when you want it). Some hotels require a minimum or maximum stay and do not offer the biggest savings during holiday or other blackout periods. Reservations usually cannot be confirmed more than 30 days ahead.

Prospective club members should request literature and compare the various offerings.

Keep in mind that many hotels offer discounted promotional rates to the general public from time to time - also that you will find the rates negotiable at just about any hotel if you pull in on a slow night.

Ask the clubs, too, what other travel services (rental cars, airport buses, museum entry fees, etc.) they discount and if they offer a money-back guarantee.

Here are some half-price clubs and annual fees:

-Entertainment Publications' Travel America at Half Price, Troy, Mich., (800) 521-9640; $29.95.

-Half Price Europe, Coral Springs, Fla., 305 971-6049; $70.

-First Travel Club, Schaumburg, Ill., (708) 240-2626; $59.04.

-International Travel Card, Stamford, Conn., (800) 255-1487; $49.

-Quest International of Yakima, Wash., (800) 325-2400; $99.

-Travelers Plus or World Unlimited, San Diego, Calif., (800) 843-0265; $39.95.

-Solid Gold, Vancouver, British Columbia, (604) 688-0484; coupon books about $34.

-Momentum International, Carrollton, Texas, (800) 822-5449; $50.

-Concierge, Denver, (800) 346-1022; $69.95, renewals $59.95.

-Club Costa, Overland Park, Kan., (800) 444-3998; $49.