Patsy Lewis, with a half dozen skirts, blouses, and dresses already slung across her arm, searched patiently through hundreds of secondhand garments at the Village Thrift Store in Bladensburg, examining each piece for its size, quality, and possible defects.

Finally, Lewis, an administrative secretary at the U.S. Treasury and the mother of two girls, found what she was after: a pant suit for herself for $1.50, a dress for one daughter for $2.00 and a dress for the other priced at only 25 cents.

"Basically, we shop here to save on the family budget," said Lewis, who with her husband, Johnny, a Metro bus driver, earned about $35,000 last year. "With price of food, gasoline and everything else being so high, we no longer have the money to buy a lot of new clothes."

The Lewises, who live in Hyattsville, are among a growing number of families in the metropolitan Washington area who, in the face of spiraling prices, are saving as much as 50 percent on their annual clothing bill by shopping at secondhand shops.

Since 1976, stores such as Village Thrift Store, Kids' Stuff in upper Northwest Washington and the Clothes-Go-Round in Arlington, for example, report they have experienced a steady annual sales growth of between 20 and 30 percent, with their clientele ranging from families who cannot afford new clothes to the well-to-do who can spot a designer label from 50 paces.

The appeal of such stores is reflected in their rapid growth. In 1976, the yellow pages of the metropolitan area telephone directory listed 23 stores selling used clothes. The latest directory list 35.

And nationally, a Washington Post-ABC News poll published earlier this month, found that 29 percent of persons surveyed said they are shopping at secondhand stores as much as possible and another 20 percent said they occasionally shop secondhand.

While it is difficult to get comparative statistics, sales of secondhand clothes appear to be growing much faster than new clothes sales, which still make up the overwhelming bulk of apparel purchases. For example, according to U.S. Department of Commerce statistics, all sales at Washington area department stores, with apparel making up a major portion, increased from $1.3 billion in 1976 to $1.6 billion 1980, an increase of roughly 25 percent over the last five years. That stands in contrast to the more than 100 percent growth reported by secondhand stores in the area.

"I believe that buying clothes at thrift shops is simply good consumerism," said Virginia Knauer, President Reagan's consumer adviser, adding that the trend toward more secondhand clothes is nationwide. "There were once people who needed to save money by buying secondhand, but hesitated because they felt it would be a pubic embarrassment. Now they find that even some wealthy people are looking for secondhand bargains."

A Metropolitan Washington family of four typically spends between $800 and $1,800 a year, depending on income, to add to or replace items in an existing wardrobe, according to the Bureau of Labor Statistics.

Although most thrift store shoppers generally buy a selection of items to wear in combination with new pieces, a person shopping exclusively in secondhand shops could save between an estimated 30 and 50 percent a year on clothing, according to Anna Aldama of the D.C. Office of Consumer Protection.

"But we've found that a large number of the secondhand shoppers in the Washington area are middle-income families looking for quality merchandise for a low price," she said. "Lower-income families -- the ones who could best benefit from buying secondhand -- are often resentful that they have to use secondhand stores."

Deanie Stokes of Cheverly, who frequently shops at the Village Thrift Store, said she recently paid $1.50 for a virtually flawless white sailing jacket, trimmed with a thin, blue border. Its "Garfinckel's" label was still intact as was the name of the maker, White Stag, a manufacturer of quality sportswear. Stokes said she had priced the same jacket new at local stores for more than $30.

"When I wear this jacket out boating, I'll be the only one who'll know I didn't pay $30 for it," said Stokes, a housewife who said her husband, Marvin, earns $45,000 a year as a federal employe at the Pentagon. "We don't have to shop secondhand, but I think it's crazy not to when you can get good bargains like this."

In the same store, Gloria Johnson of Palmer Park, who said she has to budget tightly to manage on the $17,000 a year her husband earns as a janitor, said she shops buys secondhand clothes for herself, her husband and their son and three daughters.

"I can dress my girls out of here for about $2 each and a can find nice things for my son for about $3," said Johnson, who was carefully guarding a girl's white blazer and vest, selling for a total of $2, from other shoppers swarming around her. "Once I found my son a three-piece Pierre Cardin suit for only $3."

Betty Belfiore, who owns Kids' Stuff, which specializes in used clothing, furniture and toys for children, said she decided to open her store at 5615 39th St. NW six years ago after she had difficulty finding quality used clothing to outfit her five children.

"At that time, a depression was on and the negative stigma of wearing used clothes was fading," Belfiore said. "Now shopping for secondhand things is very common. It has become chic to do it. People check our merchandise before they go to a discount or highpriced retail store."

Like many stores that sell used clothes, Belfiore's shop is a consignment operation. People bring in items to be sold. When the sale is made, the store receives half of the proceeds and unsold items are returned to their owners.

Other stores, like the Village Thrift Store, buy used clothing in bulk from charitable organizations who have received the merchandise as donations.

"People who once were not so label conscious now hunt for the big name labels that usually assure a certain standard of quality," said Belfiore, who noted that her stock frequently includes such popular children's wear labels as Buster Brown, Healthtex, Polly Flinders, Silvia Whyte, and Florence Eiseman.

Registered nurse Ivy Lutz of Arlington, while browsing among the Calvin Klein jeans and the Diane Von Furstenberg designer dresses recently at the Clothes-Go-round, stumbled across what she said was her best buy yet: a raw silk jacket in beige, with satin trim for $10. A salesperson in designer sportswear at the Lord & Taylor in Falls Church said such a jacket would sell for more than $100 new.

Antique buyer Michelle Malcolm, 29. of Silver Spring, who came shopping at the Village Thrift Store recently wearing a $12 fur stole and a flaming red 1940s blazer she bought for 75 cents, said that the experienced secondhand clothes shopper can spot quality from a distance.

"I select clothes for their quality and their antique value," Malcolm said. "After the experience of looking through thousands of garments, a shopper can eventually become skilled at quickly selecting the best value for the price he's asked to pay."