By 9 a.m. on a Saturday morning, the scattering of parking lots west of Central Expressway on Ross Avenue, is full. Vendors, ranging from business owners to people cleaning out their offices, have settled into rows in the empty lots along Ross, displaying electronic equipment of all varieties in the trunks of cars, on fold-out tables and under pitched tents. Several hundred shoppers peruse what the vendors have to offer.

The monthly Sidewalk Sale — a flea market for the computer era — is in full swing.

What began as a small meeting of ham radio buffs in 1969 outside Wholesale Electronics, a local staple at the time for radio equipment, has grown to a collection of hundreds of electronics vendors, making it one of the largest such gatherings in the nation.

“It’s one of Dallas’s best-kept secrets,” said John Leedom, former Texas state senator and the only remaining active founding member of Wholesale Electronics.

Thousands of electronic enthusiasts — 2,000 to 3,000 by Leedom’s estimate — assemble the first Saturday of every month to shop for reduced-price electronics such as computer hardware and software, cell phone accessories and video games.

Between 150 and 200 vendors flock to the sale each month, paying between $10 and $50 for a “lot” on which to sell equipment to potential buyers. Most sellers begin unloading their merchandise at midnight on Friday, when more experienced bargain-hunters do their shopping. According to www.firstsaturday.com, the event’s Web site, some vendors sell out by 3 a.m. on Saturday.

The sellers entice customers with prices lower than those commonly found in larger retail chains, lower because the equipment is either surplus from businesses or, more commonly, part of an already improved-upon — but still viable — generation of technology.

Many video-game aficionados are well-versed with the frenetic pace of development in the computer industry. Staying abreast of the changes becomes difficult given the expensive nature of computer upgrades, which gives the Sidewalk Sale increased appeal.

“I think this can market to [computer] gamers looking for hardware to make modifications to their systems,” said Rockwall resident Tim Conday, a 10-year veteran of the flea market who sells decals and stickers for ornamenting computers and has an interest in computer gaming.

Plano resident Daniel Powell, selling various CD and DVD drives out of the trunk of his van, also described the event as “gaming oriented” in many ways — with added allure for younger enthusiasts on a budget.

“Seeing that a lot of [college students] don’t have a lot of spare money, this is good for bargain hunting,” said Powell, who participated in his second First Saturday on Nov. 6.

But those sellers who do not cater to video gamers have also carved a niche for themselves as well. A vendor named Dale — preferring to be known as Mr. Ink Jet, the namesake of his Waco-based company — has sold ink cartridges and refills on First Saturdays for 12 years.

“Business has been real good — I mean, I’m still here,” Mr. Ink Jet said. “This appeals to a lot of different people from all walks of life.”

The vendors have evolved from a core group of ham radio connoisseurs who gathered regularly outside the Wholesale Electronics building before it moved from its original location, at Haskell and Central Expressway. The small group met there monthly to swap old equipment and buy new equipment until the late 1970s, when Wholesale Electronics changed locations to its current Ross Avenue site.

As personal computers emerged in the 1980s and 1990s, the Sidewalk Sale focused more on computers, causing the emphasis on radio equipment to fade and making the sale what it is today, Leedom said.

Though he wouldn’t comment on the future of the event, Leedom said that in the past few years, vendor participation has declined due to the Internet’s expanded role in such interpersonal commerce.

But, despite the decline, Leedom said he still believes the Sidewalk Sale can appeal to college students.

“If people know what they’re looking for, then they can usually find a bargain,” said Leedom, who still runs the lot for Wholesale Electronics. The lot is generally open every other Saturday and offers surplus from the business’s inventory.

Sellers and buyers will congregate for the next Sidewalk Sale on Dec. 4. Despite the twilight shoppers on Friday night, the largest crowds appear Saturday morning. Most vendors leave by early afternoon.