Are house prices falling? Nothing interests buyers -- or sellers -- of homes today more intensely than whether it's possible to shave a few thousand dollars from the price.

If a house is being sold voluntarily -- as the majority of homes are -- the answer is no. People generally take their homes off the market in poor times, rather than accept a price cut.

But some people have to sell because of divorce, a growing family, a new job, or a prior committment to buy another house. In these cases, prices are more negotiable than they were last year.

The median price of newly built homes reached a peak of $66,000 last September, then declined through the rest of the year. Builders carry high-interest loans on the houses they erect and can't afford to hold out for top dollar in a poor market. In December, the most recent data available, the median price stood at $62,300.

Existing-home prices peaked in July at a median of $57,900, edged down to $55,600 in November, then rose n December to $56,500. Owners of existing homes generally can be choosier than builders about when to sell, so -- except in special circumstances -- prices aren't as soft.

The median price, incidentally, is the exact midpoint; the same number of houses where sold above and below that price.

(Another housing number often published is the "average price," which rose over $72,000 in December on newly built homes. But the average is skewed by the sale of a few homes costing $1 million and up. The Median price is a fairer representaton of the current housing market.)

People who haven't yet bought homes and who see the median-price reports in the newspapers, may think they're completely priced out of the market. But half the existing-home sales in the United States in December were for less than $56,000 -- which is where first-home buyers should look.

These houses are not in preferred neighborhoods and may be unobtainable around some major cities or in overheated markets like California. But in much of the United States, the "first house" still does exist, and proviedes young people a toehold in the real-estate market, from which they can later trade up.

Just two weeks ago, the National Association of Home Builders was predicting that the median price this year of newly built homes would rise to $68,000. But the Federal Reserve's decision last week to let interest rates slip up a notch reduced this forecast to $67,500.

If that proves to be correct, it means a housing-price increase this year of only 7.3 percent -- sharply below the 12.7 percent of 1979 and 14.1 percent of 1978. If you buy a house now and have to sell by year end, you might not make any money after real estate commissions and other moving expenses.

The forecast for existing homes in 1980 is in the neighborhood of $61,500.

Richard Marcis, chife economist at the Federal Home Loan Bank Board, thinks that weak housing prices could last through the first half of the year, then pick up in the second half when mortgage rates stabilize, as he expects.

High interest rates will sharply reduce the number of new homes built this year, perhaps to the lowest level since the recession in 1975. But the high demand for homes continues unchanged. Kenneth Kerin, of the National Association of Realtors, says that a phone survey of real estate offices last week found high traffic -- a lot of people looking, though few were buying.

"There's a big pent-up demand," he says. Assuming that an economic slowdown does finally put a cap on mortgage increases -- for the present at least -- browsers should turn into buyers and house prices will resume their climb. The reduction in the number of houses built only helps the price for houses already in existence.

There are, of course, a lot of regional variatons in house prices that don't show up in the national indexes. Boston, for example, is weak, while much of California continues strong (although a lot of home value vanished in the mudslides around Los Angeles last week).

Kenneth Thygerson, chief economists at the U.S. League of Savings Associations, says that bad weather months are the best time to buy. "People don't move as much in winter," he says, "so things are slow."