Among the ways to trim the cost of a ski vacation this season:

- Drive to your destination. Instead of flying, four skiers in a car sharing the cost of gas can each save hundreds of dollars on the cost of a ski holiday. Families who opt to drive reap similar savings.- Ski mid-week. Most U.S. ski resorts reduce lift, lesson and equipment-rental prices on weekdays. This season, a group of 17 prominent Vermont ski areas is introducing new "Vermont Sunday Take-Off Packages." The packages offer reduced rates designed to appeal to skiers willing to start their vacation on a Sunday afternoon or Monday morning.

- If you decide to fly, fly mid-week. For years, skiers bound for a traditional ski week have booked their departure flight for Saturday and flown home the next Saturday or Sunday, making the weekend a peak period for air travel to mountain destinations. As a result, weekend air fares often are more expensive - if you can find an empty seat. One reason for the weekend crush has been that many resort lodgings required a minimum seven-night stay from Saturday through Friday. Increasingly, however, this policy is being abandoned.

Advance Reservations of Park City, a tour organizer specializing in 26 Rocky Mountain ski resorts, has put together numerous week-long packages that begin with a Thursday flight to take advantage of lower air fares. Among the destinations is Winter Park in Colorado, which Jolene Sabey, a senior reservationist, cites as an excellent value for family skiers. The resort is one of the state's oldest and largest, but it lacks the classy reputation of Aspen and a ski vacation there tends to be cheaper.

A customized seven-night package for a family of four (one child under 12, one over 12) at Winter Park begins at about $2,900. The rate includes round-trip air fare from Washington, transportation to Winter Park, seven nights' lodging in a one-bedroom condominium with a living-room sleeper, lift tickets for four, trip cancellation insurance and taxes.

The condo is located on the Winter Park's free shuttle-bus network, so a rented car is not necessary. The only additional expense is lessons and meals, some of which you can prepare in the condo to save money. For information: Advance Reservations: 800-453-4565.

- Shop around. Many ski destinations have central reservation offices with toll-free numbers. You can check with favorite resorts for the best lift and lodging package for your budget. You may be able to find last-minute bargains or budget packages not listed in the standard brochures, according to the United Ski Industries Association. Toll-free numbers can be obtained from the 800 Directory, 800-555-1212.

- Ski the off-peak weeks. Each resort sets its own calendar, but the off-peak weeks beginning before Christmas and from the end of March to closing in April offer the best bargains. At some resorts, January is also considered an off-peak period. At Crested Butte, the daily lift-ticket price for adults is $25 from Nov. 22 to Dec. 14 and April 1 to April 7. From Dec. 15 to March 31, the peak-season price is $35 a day.

- Skip the giants. The big resorts offer more exciting skiing, but you also pay $35 a day or more for a lift ticket. A number of smaller resorts offer good skiing on substantial acreage at cheaper prices.

Among those cited by the United Ski Industries Association: In Utah, Brighton, $20 for a daily lift ticket, and Alta, $21; in Colorado, Berthoud Pass, $17, Ski Cooper, $18, and Monarch, $23; in Idaho, Brundage Mountain, $19; and in Montana, Bridger Bowl, $21.

- Search out special deals. At various times of the season, resorts offer discounts to seniors, college students and others. Parents may want to find special deals on child-care arrangements or price breaks on lift tickets for youngsters. Take advantage of any that benefit you.

At Steamboat in Colorado, children 12 and under ski free when their parents purchase a five-day lift ticket and stay five days at a participating lodge or hotel. A maximum of two children qualify for a two-parent family; one child for a one-parent family. Free equipment rentals also are offered on a one-for-one basis for each parent who rents.

- Dine cheaply. The budget-saving tactics you adopt on a summer vacation can be put to use on a ski holiday. Even Aspen has cheap burger cafes and spaghetti houses to cut the cost of meals. The season I slept in an Aspen dorm, I also saved additional money by toting raisins and nuts in my pockets so I wouldn't have to pay high cafeteria prices on the slopes. I preferred a hot meal, but you do what you must to be able to ski.