Christine Whitney of Boston tries on her prize, a Nina Ricci Fourrures sheared mink-lined impermeable purchased at the Sloans and Kenyon's February Auction of Couture and other Designer Fashion and Jewelry in Chevy Chase, Md., on Feb. 23, 2013. About 20 percent of the clothing from the Sloans & Kenyon auction this Saturday was from the estate of Annelise Fitzgerald, whose husband was ambassador to Ireland from 1992-1993. (Marvin Joseph/THE WASHINGTON POST)

The bidding begins at $20 and leapfrogs to $50 as auctioneer Steve Little, nattily dressed in a navy pinstripe suit and purple-pattern tie, jokes with and coaxes several dozen would-be shoppers in the Wisconsin Avenue basement of Sloans and Kenyon Auctioneers and Appraisers. “It’s a good day to buy something,” he says. The ante is upped to $80. In his mellifluous voice, Little pushes, “Looking for $90?” It’s a no-go. Lot 30 is sold for $80.

The 1960s silver lame and gold boucle evening coat with rhinestone buttons labeled Saks Fifth Avenue is a far cry from the antique snuff boxes and tole trays that are the Bethesda auction house’s typical fare. The find was part of more than 400 pieces of vintage and couture clothing and jewelry that were on the block at Saturday’s sale.

Sloans and Kenyon held its first vintage and couture clothing auction a year ago, as an experiment. That Saturday’s event was the auction house’s fourth in 12 months is testament to it having found an only-in-Washington kind of niche. Sloans and Kenyon is one of only a handful of houses around the country holding such sales.

“Washington is an ideal location for these auctions; people’s occupations here require that they dress elegantly,” says Lisa L. Jones of the auctioneer’s recently created costumes, textiles and fashion department.

So what are you likely to find? Lavish ball gowns and little black dresses from the closets of well-established Washingtonians including Washington Times Herald editor Eleanor Josephine Medill “Cissy” Patterson and Annelise Fitzgerald, wife of the one-time U.S. ambassador to Ireland, William Fitzgerald. Many of the sellers say they no longer have the social life that requires their former wardrobes.

The chance to own and wear such treasures brings an eclectic crowd to Bethesda on a rainy Saturday morning. They mill about, checking out mannequins decked out in a Pierre Cardin black crepe tiered evening dress, an Ungaro rust-colored gown and wrap and a flamenco evening gown. They browse glass display cases featuring Yves Saint Laurent necklaces, bracelets, alligator handbags and cloche hats. And at 11 a.m. as the auctioneer goes to the podium, they take their seats on folding chairs.

To be sure, there are the usual Washington suspects sporting Burberry jackets and Tory Burch. But the new guard has turned out too.

Mary Margaret, a high school senior at Oakcrest High School in McLean and confessed vintage lover who wants to work in fashion, says, “Clothes aren’t made this way anymore,” as she proudly shows off her own 1980s crested blazer.

Twenty-five-year-old law school graduate Amyia McCarthy, dressed in leather leggings, faux fur vest, multicolor sequin sandals/boots and a chartreuse bag, says, “I heard about the event last night from someone I met at a phone store in Friendship Heights.”

Antiques collector Courtney Rackley Schwartz, 36, speaks for most when she explains why she’s at the auction: “It’s better to have one quality fashion item than 10 disposable ones from H&M.”

Buying at auction is definitely different than buying at the mall. To help mitigate the possibility of a frenzied spending spree followed by an acute case of buyer’s remorse, Sloans and Kenyon produces a printed and online catalogue describing each item and offering a suggested price range, based on what similar items have sold for in the past. Photographs don’t always tell the full story, however, especially when buying 40-year-old clothing. (For example, the flamenco gown will need to have the lace reattached to the bodice.) So bidders can come in before the auction to check out items that will be offered. Once the auction starts, there’s a dizzying combination of live, online, placed-in-advance and phone bidding. Although most of the bids come from people attending the auctions, the frantic nature can lead to the kind of overspending that has made auctions such sitcom staples. On Saturday, a bidding war over a Chanel colorless glass necklace sent the price for the costume piece careening to $2,000; that was 10 times the low end of the catalogue estimate. A determined telephone bidder won the contest.

After four hours of bidding, the last few lots are called and it’s time to line up to pay and take home the spoils.

Mary Margaret has scored a brown rabbit fur knee-length vest with brown satin lining for $300, half its low-end estimate of $600. It’s even a better deal because her dad picked up the tab.

Forty-something artist Vivienne Kelly lost out on the tiered Pierre Cardin, left the auction but came back to put in a winning bid for the custom flamenco evening gown, paying $425. It was more than she wanted to spend, but she is nevertheless pleased with the purchase she intends to wear to the Kennedy Center.

Afshaneh Taki, 32, a visual stylist for Neiman Marcus in Texas, stopped by the auction on her way to meeting a friend in Baltimore. She left with her arms full but was most delighted with her 1950s brocade cocktail dress for $120 by Ceil Chapman, said to be Marilyn Monroe’s favorite designer.

Not everyone leaves with the dress of her dreams: Hillary Greenwald, 31, who works in property management for Bernstein, went home empty-handed, as did about one-third of the attendees. “Everything I liked went for too much,” she says at day’s end. And Amyia McCarthy lost out on the 1980s Valentino dress laced with a red taffeta bows at the waist that she had her heart set on.

Despite the competition on some sought-after items, about 25 percent of the day’s auction items did not sell, Sloans and Kenyon says.

Still, the next auction is already on the calendar for May. The desire to get a buy that no one else in your circle will be wearing, coupled with the shopping camaraderie and adrenaline rush that the auctions instill keeps Washingtonians such as Schwartz coming back.

“It’s exciting and fun, addictive,” she says as she carries her $275 Givenchy fuchsia silk dress to her car.