Prince William County, in the midst of a retail development boom, is attracting the latest trend in retailing: cut-price stores serving well-educated, money-conscious suburbanites.

And Prince William is capturing the cream of the crop from this cut-price market.

The Washington-based firm Western Development Corp., known for its classy specialty mall, Georgetown Park in Georgetown, chose Prince William to build the nation's largest outlet mall. Just off I-95 in Woodbridge, Potomac Mills is due to open this summer. It will offer 1.3 million square feet of space for direct-from-the-manufacturer shops and discount stores.

Trammell Crow, one of the nation's largest shopping center developers, also chose Prince William County for its first retail ventures south of the Potomac River. It plans two shopping centers on Sudley Road in the Manassas area, which partner Peter Henry expects will house cut-price stores along with conventional retailers.

Although Prince William has more of a blue-collar image than its Northern Virginia neighbors, developers say that is not the reason bargain-type stores are flocking to the county.

Rather, Henry says, Prince William has the opportunity to be in the forefront of new trends in the retail business because its retail base is developing later than the rest of Northern Virginia's.

Western spokeswoman Debbie Staats agrees: "It's following the trend of the baby boom generation, which wants the best quality but is not prepared to pay outrageous prices."

Shopping center specialist Harold J. Carlson adds fewer of today's consumers can afford department store prices -- even if they wanted to -- so are turning nationwide to cut-price stores.

"It was spawned probably by the recession. . . . With the rising cost of housing, petroleum products and utilities, there were fewer disposable dollars available, but they didn't want to sacrifice quality," Carlson said.

Recognizing this, some merchants began buying the same goods as department stores but negotiated better factory prices and then kept the price on the sales tag down by minimizing their overheads, Carlson said. Locating in the suburbs, where land is cheaper and more plentiful, is one way for these cut-price stores to reduce overhead, he said.

At the same time, to succeed cut-price stores need an educated consumer, someone who can recognize top-quality goods even though the brand label might have been removed and the store looks less prestigious, said Jack Gould, shopping center consultant with the Washington firm H.S.G.-Gould Associates.

Statistics suggest that Prince William County offers cut-price retailers all of these ingredients deemed necessary for success, and more.

Land there still costs 10 to 20 percent less than in the closer-in Northern Virginia suburbs and there are large tracts left undeveloped.

In addition, the population is well educated -- 66.3 percent have attended college -- and is growing rapidly. Today an estimated 177,000 people live in Prince William County and the Metropolitan Washington Council of Governments predicts an 82.4 percent population increase over the next 15 years. With 45 percent of the population between the ages of 20 and 44, most Prince William residents fall into the baby boom category, U.S. Census figures show.

On top of this, Prince William County's average household has 3.26 members and a median family income of $34,205, giving it the highest retail sales per household in Northern Virginia, according to the county's economic development office. Median means an equal number of families earn more and a number earn less than that figure.

These figures lead Henry to say of Prince William: "It's young, it's healthy, it's vibrant. I think you're going to see growth that is hard to repeat elsewhere in the country."

Other retailers besides the cut-price stores are recognizing the county's potential. Traditional shopping center development is growing as well.

County figures show that Prince William is on the verge of a 175 percent growth in its retail base. The County's Office of Economic Development counts 2.9 million square feet of retail space in Prince William today. The Department of Development Administration this year has approved site plans for an additional 2.3 million square feet. Other applications, if approved, would add 1.4 million square feet of retail space. Meanwhile, Ernest W. Hahn Inc., a West Coast developer, is holding another 1.4 million square feet of land already zoned for a regional mall opposite Potomac Mills at Interstate 95 and Opitz Boulevard in Woodbridge.

If all this land were developed as planned, Prince William County would have 8 million square feet of retail space, roughly equivalent to 3 1/2 times the amount of space at Tysons Corner in a county less than one-third the population of Fairfax County.

Retail developers give the same reasons for their interest in Prince William.

"It's such a phenomenal growth area and the consumer in Prince William is far more affluent and educated than the existing retail space caters to," said Paul Himes, a real estate developer who expects to unveil plans for a new shopping center in Manassas next week.

Baltimore developer James A. McDonald says he was looking for the best retail location in Northern Virginia for his first project south of the Potomac. He settled on a Prince William site when he found a location that had 60,000 people within a three-mile radius, with a combined purchasing power of $21 million annually.

"They are very educated and demanding people who are willing to buy but want quality," McDonald said. He is planning a 319,000-square-foot "quality" shopping center at the junction of Smoketown and Davis Ford roads in eastern Prince William County. Architectural drawings show four buildings with atrium entrances clustered around a paved 1.2-acre courtyard where three fountains play.

Even existing shopping centers are expanding. The Mall At Manassas has filed plans to add 540,000 square feet to its 393,273 square feet mall on Sudley Road. Next door, Leggett Department Stores Inc., the apparel and home furnishings store, hopes to double its 40,000-square-foot building.

"Population-wise, income levels, employment growth, any way you look at it, it's a very active community," said William E. Leggett, the company's vice president for real estate. But he concedes he is concerned about how the influx of cut-price merchandisers will affect his traditional department store.

"Obviously, if they're selling the same products at significantly lower prices, we're going to have to reduce our prices. It's just becoming more competitive," Leggett said.

However, Gould says that the conventional wisdom is that cut-price stores and traditional stores can coexist. Hence Trammell Crow is considering both types of stores for its 400,000-square-foot mall on Sudley Road that will front the 413-acre mixed-use developments owned by Paradise Associates outside Manassas.

Although Prince William today appears to be inundated with shopping center applications, John Gessman, director of the county's Office of Economic Development, calls the influx nothing but a response to pent-up demand.

The 1980 census showed that retail sales in Prince William were $16,146 per household, the highest in Northern Virginia, but the downturn in the economy robbed developers of the financing needed to invest in large malls that would enable them to take advantage of these figures, Gessman said. Now that the future looks brighter, developers are ready once more to try and capture some of that retail spending locally, he said.

Grady Tucker, president of the Rockville-based shopping center consulting firm Larry Smith and Co., said the figures look promising for retail development in Prince William. A regional shopping center with two or more large anchor stores needs a residential base of more than 175,000 people who spend 8 to 9 percent of their income in a department store. Prince William passes that threshold and continues to grow, he said.

As for the cut-price stores, they favor locations where the population is above average in income and in education but where people are heavily in debt, he added.

"New cars, new homes, new children, big insurance policies, you've got a lot of money tied up. These people are very careful about how they spend their money," Tucker said, which is exactly what outlet stores relish.

Major shopping centers planned or under construction in Prince William include:

*Potomac Mills, developer Western Development Corp., 1.3 million square feet for a factory-direct mall at Telegraph Road in Woodbridge. Opening planned for phase one in July.

*The Mall At Manassas, 540,000-square-foot addition to an existing 393,273-square-foot mall on Sudley Road in Manassas. Preliminary plans filed.

*Trammell Crow Co., 400,000-square-foot fashion mall on Paradise Associates property on Sudley Road in Manassas, Preliminary plans filed.

*Prince William Square, developed by Jamestown Associates of Atlanta, 247,260 square feet including a Bradlees store, on Smoketown Road, Woodbridge. Ground broken.

*Smoketown Plaza, developed by BTR Realty of Baltimore, 400,000 square feet at the junction of Smoketown Road and Davis Ford Road in eastern Prince William. Ground broken.

*The Center, developed by James A. McDonald Inc., 319,000 square feet at the junction of Smoketown Road and Davis Ford Road in eastern Prince William. Rezoning application filed.

*Lake Ridge Commercial Center and Hedges Run, 230,000 square feet, including a Giant food store, on Old Bridge Road in Lake Ridge. Preliminary plans filed. Earnest W. Hahn Inc., 1.4 million square feet for a regional mall at Opitz Boulevard in Woodbridge. Rezoned in 1973 but no plans submitted.