The American dream: you may be able to buy in now

One of the first things the Lanes, of Newburyport, Mass., did when they decided to buy a home was to pare down their monthly bills. The second car was sold, and ''when we cut $25 here, $25 there, it really began to add up,'' says Mrs. Lane, who will be moving in May.

The Lanes are typical of first-time buyers who are coming out of the woodwork in droves to make a home purchase that only a short time ago was beyond the consideration of most young couples.

For the past several months, cheery real estate agents and smiling builders have been sounding the call that the American dream is once again affordable. And with good reason: Interest rates have dropped from around 16 to 17 percent earlier last year to a current norm of around 13 percent, making it possible for many more people to qualify for a mortgage. Prices on homes are holding steady, and many are considerably cheaper than in the boom years of the late 1970s.

In addition, housing starts are expected to be around 1.5 million this year, the National Association of Home Builders says, meaning that there will be a reasonable amount of new homes for those who want them. And builders and agents alike are tailoring homes and mortgages to the needs of today's buyers.

Two major changes are noticeable in the housing market: First, mortgages come in any number of shapes and sizes, confusing even many experts. Second, housing is getting smaller, dropping in size since 1979 by about 150 square feet. This does not mean there has been a drop in quality; rather, many builders are offering homes that have a more efficient use of space, are easier to maintain, and appeal to smaller families or singles.

There are many things to consider before making a down payment on a new home. The most pressing, of course, is how much of your income you can safely devote to a home - the mortgage, utilities, taxes, and insurance. Home prices have escalated more rapidly than income in recent years. The typical monthly mortgage payment jumped from $352.72 in 1978 to $624.70 last year. Therefore, notes Don Ursin, president of Coldwell Banker Thorson, the range of 33 to 35 percent of income is as common now as 25 to 28 percent used to be. Generally, Federal Housing Administration and Veterans Administration loans allow a higher percentage of income to be devoted to a home. (The maximum mortgage available is

A decision on what income percentage you can afford to devote to shelter will outline what towns or suburbs are good possibilities. In the case of the Lanes, a move to nearby Salisbury meant a saving of $20,000 because of lower land and housing costs. Then, one can consider mortgage plans.

The most popular, and the most risk free, is the standard fixed-rate, fixed-term mortgage. This plan, usually extended over 25 to 30 years, locks in the payments each month so that the buyer knows exactly what to expect throughout the term of the mortgage. Adjustable-rate mortgages - in which the rate is changed to match the current cost every 1, 3, or 5 years - almost replaced the fixed-rate plan during the period of extremely high interest rates, because of buyers' hopes of obtaining a lower rate later on. Now, however, the fixed rate is more appealing to those who figure rates have bottomed out.

One option for home buyers who anticipate a rise in income over several years is the growing-equity mortgage, or GEM. The initial payments are the same as a 30-year mortgage, but then increase by 3 to 4 percent each year. The mortgage is paid off in 15 years, thereby saving the buyer a considerable amount of interest.

Similarly, there is the graduated-payment mortgage (GPM), designed to help those with lower incomes to qualify for their first mortgage. The buyer starts with low payments and builds them up gradually. By the end of five years, he will be paying full amounts on the mortgage.

Although some experts feel there is a fair amount of risk in this plan, it is quite popular. The catch is negative amortization, which means that the initial payments do not reduce the principal of the loan. Thus, if you have to sell, it is possible that the outstanding loan balance may exceed the value of the house. Nevertheless, many feel that this is a good way for young buyers to start out.

About the most important thing you can do in house-hunting is to find a good agent that you can trust. And, once you do, advises Marcia Clopton, president of CBS Realty in Washington, D.C., ''Level with the realtor as to exactly what your money situation is. And then look at things in that range - don't run off looking at homes that are $15,000 to $20,000 more than you can afford.''

Ms. Clopton, who feels that now is a very good time to buy, says that any couple with two incomes and is now renting should purchase a home for the tax shelter. She adds the practical advice that prospective buyers should have a qualified engineer inspect the house for soundness, and research any nearby undeveloped property to find out what is going to happen to it.

Median sale prices, new and existing homes

New homes Existing homes 1979 $62,900 $55,000 1980 64,600 62,6000 1981 68,900 66,500 1982 69,300 67,700 Projections: 1985 87,300 85,100 1990 122,000 118,000 Source: National Association of Home Builders