Here are a number of vacation discounters, some of which require memberships and some which don't, that may be able to cut your costs if you are willing to do a little extra planning or work:

- Access International promises the lowest-priced fares to Europe normally available. It also offers flights to Eastern Europe and plans to offer flights to the Caribbean by April and to Mexico by May. Payment is by Visa or MasterCard if you like. You receive your ticket via Federal Express (you pay for mailing) about four days before departure. The service confirms the time but you must call the airlines to get the flight number. Call 212-333-7280.- Destinations Unlimited specializes in trips to Europe and the Orient, especially Japan, Hong Kong and Seoul. Prices are usually 30 to 35 percent lower than the lowest coach fare. Flights may leave any day. Payment is by certified check. Call 212-980-8220.

- If your eye is toward the Caribbean, check out South Florida Cruises in Fort Lauderdale. The company bills itself as "the nation's leading cruise specialist" that can offer passengers savings because it buys millions of dollars of advance space from the cruise lines. Average savings on a week-long cruise is $700 to $800 per cabin, and passengers can often book 14 months in advance. The average price of a week-long cruise, including air fare, is $2,500 to $3,000 for two people sharing a cabin. Call 1-800-327-SHIP.

Another option is discount travel organizations that charge an annual membership fee that covers a household and sometimes even friends. Members get access to telephone hotlines or frequent mailings with constantly changing trips. Discounts are often 20 to 30 percent and as high as 60 percent.

- Moment's Notice, based in New York, calls itself a "clearinghouse" for air seas and cruie cabins that are still unsold as the day of departure nears. Notice for Caribbean and European tours, African safaris and treks through China may be a week to three weeks in advance. Notice for cruises may be two months. Membership is $45. Call 212-486-0503.

- Vacations to Go, based in Houston, charges $29.95, and offers trips out of cities such as Los Angeles, New York, Boston and Chicago as well as Oriental and Hawaiian cruises. Notice is frequently three to four weeks for a land package and a month or two months for cruises. To get an information kit call 1-800-227-1992.

- Discount Travel International, based in Narberth, Pa., charges $45, and gives two weeks' to two months' notice on every kind of travel offering on its hotline. Additionally, the company promises a 5 percent discount on any trip advertised. Call 1-800-824-4000.

An excellent way to see Europe and America on the cheap is to stay at a college dormitory for an average $12 to $25 a night. Many are located in beautiful settings with convenient transportation to major cities. The new edition of U.S. and World Wide Travel Accommodations Guide lists 600 campuses, including some in Paris, London and Copenhagen, with single rooms, shared rooms and apartments. Many welcome children. Sports facilities are available. And those in Europe often include breakfast. Send $11.95, postage is free, to Campus Travel Service, Dept. P, P.O. Box 5007, Laguna Beach, Calif. 92652 (714-497-3044.)

If you can do without luxuries, check out the "Y's Way to Visit North America and Worldwide" which lists overnight accommodations at 103 YMCAs. The average price is $22 a night. To get the 1989 booklet, end 45 cents and a self-addressed, stamped envelope to Y's Way International, 356 West 34th St., New York, N.Y. 10001. (212) 760-5856.