FTER making the switch from a five-bedroom house in Arizona to a two-bedroom Manhattan apartment, David and Eileen Garrahan found their closets a bit cluttered. A flyer they spotted in the laundry room of their apartment building promised relief, offering to help them convert treasures to cash on eBay without ever turning on a computer.

The Garrahans bit.

"You get to a point where this stuff collects dust, and getting rid of it takes a lot of time and effort," said Mrs. Garrahan, who is familiar enough with eBay to know what she thinks of it. "Tedious," she said.

Their conduit to the online auction world was a neighbor in their Upper West Side building, Mike Beeferman, a 34-year-old eBay devotee who proceeded to make digital photos of the Garrahans' pottery, bronze sculptures, vintage nude photos and porcelain, and to write descriptions of the items.

Mr. Beeferman's flyer, a decidedly nondigital approach, helped him get his virtual consignment shop running seven months ago. His goal was to help people who were too strapped for time or too timid about the Internet to sell their belongings online, and possibly support himself doing it.

"People have things that they know are worth something, but they really don't know how to get rid of them," said Mr. Beeferman, who worked in the music industry and studied e-commerce at Columbia University. "I try to list it the best way possible for the most money."

Mr. Beeferman is hardly the first person to come up with the idea of starting a small business tied to eBay. Almost from its beginnings, the online auction service has inspired entrepreneurial visions; eBay has found that one-fifth of all sales at its Web site now involve trading assistants.

In acknowledgment of that trend, the company began a formal program for the assistants in February 2002. It allows them to advertise their services free in an online directory that can be searched by ZIP code or merchandise category, and it provides subsidies for local print advertisements.

More than 21,000 people worldwide have registered, said Walt Duflock, manager of the trading assistant program for eBay. To qualify, a seller must have a minimum of 50 feedback comments from previous eBay sales, at least one transaction in the previous 30 days and a positive rating from at least 98 percent of his customers.

Buying goods on eBay requires little more than the time to browse, a few clicks to enter a bid, and a leap of faith that what you are buying will actually arrive at your door intact. But those who have sold goods at the site say that selling is not quite so simple. Posting an auction requires taking and uploading a photograph, writing a description, doing enough research to make a realistic assessment of price, and following through on a sale. In a marketplace based on trust, experienced eBay buyers are often reluctant to purchase from new sellers; veterans accrue track records through feedback that is posted online for all to scrutinize.

The cost of the assistants' service varies widely. Mr. Beeferman, for instance, charges a listing fee of $5 per item, plus 20 percent to 40 percent of the selling price. Out of that, he pays fees charged by eBay for listing goods for sale, which vary from as little as 30 cents to a percentage of the sale price, depending on the item. Gary Dorrough, a trading assistant who lives in Lahaina, Hawaii, said he was surprised that people found the eBay process so daunting that they would pay him a 30 percent commission on a sale. "A lot of people are just baffled by the whole process," he said. "This way, they don't have to do anything. That's very appealing to them."

Like Mr. Beeferman, Mr. Dorrough became an eBay devotee by selling his own belongings there. Once he had divested himself of his collection of blues records and other personal possessions, Mr. Dorrough became a trading assistant and soon found himself scouring local auctions and estate sales for bargains that he could resell. Hawaii is a transient place, he said, which is good for people in the consignment business: whenever someone moves, inventory swells.

A former restaurant manager and driver for United Parcel Service, Mr. Dorrough finds the process of acquiring merchandise an exciting challenge. "When you buy something, you have to go research it to put together an intelligent listing," he said, adding that he now makes his living through his virtual consignment shop, which he calls Granny's Attic. "It gives you an opportunity to learn about a lot of things."

It also extends the reach of brick-and-mortar consignment stores, said Howard Katon, who runs a consignment shop in Lake Worth, Fla., and does not use a computer. Mr. Katon uses a local trading assistant to post items on eBay that he thinks would take too long to sell in the shop. A photograph by Man Ray that he listed recently did not sell, but it generated an inquiry from a customer in China.

"You're dealing with the whole world on eBay, whereas I'm just dealing with a little neighborhood for my store," he said. "It's like having two stores."

In fact, many of his colleagues in the antique and consignment business have found the virtual marketplace more compelling than an ordinary storefront, Mr. Katon said. "Instead of paying rent, they're closing up and selling online. There used to be so many dealers and now it's cut down to about half."

But while many dealers may see greater opportunities in the virtual marketplace, people who have sold goods on eBay for some time say that prices are not what they used to be, and merchandise is tougher to sell than it was in the past.

"Whatever you used to put on eBay used to sell immediately," Mr. Katon said. "The best of the best is what sells today. Being that only the good stuff sells, you don't get the prices you used to get."

EBay reports that sales have increased 94 percent in the last 12 months. This extraordinary growth has altered the dynamics of the marketplace, said Rosalinda Baldwin, founder of the Auction Guild (www .auctionguild.com), a Web site focusing on trends and concerns in the online auction marketplace. In the early days of eBay, items listed online routinely fetched high prices, inflating the hopes of sellers.

"People's expectations of what something is worth is much higher than reality," Ms. Baldwin said. "We're at a saturation plateau." That conclusion leads her to question whether trading assistants can make a profit when not all items that are listed sell and the cost of listing them is high.

Phillip Davies, who now runs a virtual marketplace for antiques and collectibles dealers called The Internet Antique Shop (www.tias.com), knows firsthand the drawbacks of being a trading assistant.

Two years ago, he had an exclusive contract to help a group of antiques malls across the United States forge an e-commerce presence. The idea was to station an employee at each mall who would help dealers put their merchandise online, for a fee and a percentage of the sale.

"We had built mobile carts that you could take into a mall," Mr. Davies said. With a built-in digital camera and a wireless Ethernet connection to the Internet, each cart was essentially a studio on wheels. "You could do it all from the cart as you rolled around the mall," he said.

The business proved too time-consuming and not lucrative enough. "The hard part was nailing down all the data on all this stuff, taking it from the brick-and-mortar world and dumping it into eBay," Mr. Davies said. "To make any money, you have to take 40 to 50 percent of whatever the item sells for. You're doing a lot of work for that, but a lot of people are going to balk at that. If it was easy, everyone would be doing it."

For its part, eBay wants to encourage those who think that selling at its site is easy. It holds weekly training sessions to teach trading assistants how to market themselves, both online and off. And it pays 25 percent of the cost of local print advertisements that publicize their services and extend the reach of the eBay brand name.

"What's in it for us is more quality listings, some experienced sellers turning into higher-end sellers," Mr. Duflock said.

Trading assistants like Mr. Beeferman and Mr. Dorrough are happy to be selling online. One reason Mr. Dorrough loves the work, he said, is that he can do it anywhere. And Mr. Beeferman said he was making enough money to pay his bills, which was his goal when he started.

Customers like Mrs. Garrahan are relieved to see the clutter diminish. "When you get older,'' she said, "you want to limit the number of things you take care of.''