A sampling of volunteer vacations (prices do not include transportation):

* EARTHWATCH, 10 Juniper Rd., Box 127, Belmont, Mass. 02178.

1982 Expeditions: Black Rhino (Kenya), $1,375; Life on the Rocks (Bermuda), $1,150; The Great Barrier Reef (Australia), $650; Church and Town in Gaul (France), $1,250; Copper Traders of Ancient Cyprus, $1,000; Volcanoes of Ancient Thera (Greece), $1,330; Glaciers of the Canadian Rockies, $865; Rocky Mountain High, $885; Politics and the Chimu Empire (Peru), $1,095; Termite Warfare (Guyana), $990. Age: 16-75. Children 14 and 15 are sometimes permitted in cases where a parent will be accompanying the expedition, and where the son or daughter is mature enough to share responsibilities of the project. Cost is tax-deductible.

* UNIVERSITY OF CALIFORNIA RESEARCH EXPEDITIONS (UREP), University of California, Berkeley, Calif., 94720.

Similar to Earthwatch, but only University of California research projects are sponsored. Among the 21 1982 expeditions: Tamarin Monkeys of Panama, Balloon Observations of Solar Activity, Language Evolution in China, Diet and Disease: A Study of Traditional African Food (Liberia), Drugs From the Sea (French Polynesia). Each participant contributes an equal share to cover field and research expenses of the expedition as well as overall costs of planning and implementation. Prices, which range from $500 to $1,575, include meals and lodging and are tax-deductible. Age: 18-75.

* SIERRA CLUB, Outing Department (Kelly Runyon), 530 Bush St., San Francisco, Calif. 94108.

Service trips: cleanup, trail maintenance, and wilderness restoration, most in areas of the National Wilderness Preservation system, mixing the hard work of wilderness conservation with the pleasures of backpacking. Prices range from $75 to $190 and include all food and leadership. Because the trip cost is subsidized by the Sierra Club and donations, expenses are not tax-deductible. Minimum age: 16.

* SIERRA CLUB SERVICE TRIPS (for doctors), Dr. Bob Majors, 3508 Williamsborough Court, Raleigh, N.C. 27609.

Doctors donate their time and skill for a waiver of the trip price. Physicians are not required to work on the trip project, but many do.