When the price of silver and gold began to skyrocket last fall, a street vendor of jewelry who perfers to be known only as Billy folded his regulation 4-by-7 foot table, closed shop after 12 years on D.C. streets and headed north.

Three weeks ago, after the market had settled down and prices declined, Billy reappeared on the streets of Georgetown -- minus the gold items he had for sale last year and charging slightly higher prices, but armed with the prospect of renewed sales.

"Last year I could have melted down all my stuff and made a profit over what I was selling the jewelry for," said Billy, who maintains he sticks with street-vending because he likes being his own boss and independent of a large organization where decisions are handed down from above.

"Now I can afford to keep the business rolling because prices are back down within reach," he said.

Washington's street vendors, considered by many to be the last free and unfettered entrepreneurs in a nation dominated by giant corporations, are not so free after all. They do not carry the large overheads of more conventional businesses, but are not immune from buffeting by economic forces beyond their control. On a good day, they may make up to $100. On a bad day, nothing.

"Airline companies are jacking their prices, and gas may go up to $2.00 a gallon which affects tourism," said Mike Sodol, 17, who has sold ice cream four summers in a row for the Dream Maid Co., which has an exclusive contract with General Services Inc. as vendors of ice cream on the Mall. "We rely a lot on the economy like everyone else, I guess."

Tourism is the bread and butter of D.C. street vending, especially in the Mall area, and last year was a tough one. The number of visitors touring Washington's galleries and museums fell last year by nearly 1 million after two straight years of increases, according to Mary Combs, with the Public Affairs Office of the Smithsonian Institution.

In 1978, 24 million people toured Washington's galleries and monuments. Last year Comb's office reported a total of about 23 million.

Area weekend hotel occupancy was down, which reflects a decrease in family travel, according to Austin Kinney, executive vice president of the Washington Area Convention and Visitor Association.

The Grayline Co. reduced the number of buses it operates for its 12 daily tours of the capital, said Sales Manager Derrick Neubert. The approximate nine buses normally scheduled for each tour were cut back to five, he said.

Rising gasoline prices and an apparent fuel shortage in Washington scared away many of the expected tourists, vendors say, and sales last year fell off as much as 60 percent, some report.

"I might have been forced to go into another business if the gasoline shortage had kept up," said Ronnie W. Pickrell, a co-owner with his father of the Star Vending Co., a 50-year-old company that sells hot dogs, soft drinks and icecream. "There would have been no one to sell anything to."

Until last year Star Vending used to pay a driver to deliver supplies to the ten trucks and carts the company operates on notice from a two-way radio. In order to cut costs, Pickrell now makes the deliveries himself and has stopped using the radio altogether.

He has also had to raise the consignment percentage he pays his vendors this year. Last year he paid 20 percent on each hot dog sold; this year he pays 25 percent.

"We had to encourage them to stay," he said. "They just weren't making much money."

Street vendors' predictions for this year are optimistic, but tempered by fear of government action both here and abroad. Tourism is up from last year most say but should oil prices rise again, causing long lines at the gasoline pumps, the number of tourists coming to Washington this year may stay at last year's low levels.

Visitation levels are still low to the Smithsonian buildings but for visitors wishing to enjoy the recreational facilities in the area, reservations this year have to be made one year in advance.

"People are staying closer to home, said Sandra Alley, Deputy Director of Public Affairs for the National Capital Region of the National Park Service. Campers and picnickers along the George Washington Memoirial Parkway have increased 48% over last year, she said.

So far, however, applications for vending licenses are holding steady, an indication that perhaps spiraling inflation, gas shortages and the threat of recession have not significantly affected the trade.

Already about 1,000 vending licenses have been granted this year -- an average number, according to Joseph Richards, chief of the D.C. Business License Branch.

Richards office processed 3,745 licenses last year, about two-thirds of which went to vendors selling items other than food. Figures were not available for 1978, but Richards said there were no signifigant differences in number of type of vendor.

To acquire a vending license, a vendor needs only a tax number from the D.C. Department of Finance and Revenue. The whole process takes only "30 minutes," said Richards. The licenses are good for one fiscal year which runs from Oct. 1 to Sept. 30.

Richards estimates that about half of the licenses yearly go to independent vendors, and the other half to those working for firms that have many street representatives.

"We think (the vendors) are doing well," he said.

In addition to the tourist trade, the mass demonstrations that Washington attracts promise fast sales of specially made T-shirts ans souvenirs, according to Richards. He recalls one couple who sold T-shirts for $7 apiece during a religious rally severaly weeks ago, and made $21,000 in three days.

But a change in the kind of tourist coming to the area this year has produced some sales resistance that may have a negative effect on street vendors' sales, according to Walter Williams, vice president of the Recreation and Parks Division of General Services, Inc. that contracts with the National Park Service to operate refreshment stands and visitor services in the Mall area.

"We are seeing more an more regional visitors with no major need to buy gifts and film because they don't live that far away," he said.

Even this pattern can be lucrative for some vendors, according to Albert Reynolds, manager of market development for the Good Humor Co. A recession has what he termed a "psychological effect" on people that compels them to buy because they have done without something else -- such as an exotic vacation -- that has become too expensive.

"It is a natural tendency to treat yourself because you haven't been able to go away," he stated. "We are historically a recession business."

Tourists visiting Washington also may buy less when they find that prices of an ashtray with a picture of a national monument is 11 percent higher than last year -- and Larry Cox's fuel bill is one factor to blame.

Cox pays $40 a week -- twice as much as he paid a year ago -- to tow a booth of souvenirs to and from Mt. Vernon, Va.

"I told myself last year if this year isn't better then I'm going to give up," said the three-year veteran of vending who quit driving a tractor to be able to spend his winter months traveling on his summer income, "but so far this year has been better."

That staple of the tourists' diet, ice cream, has also jumped in price. Government price supports for dairy farmers have caused four price increases just this year for ice cream, said Joe Rosin, who owns the Dream Maid Co.

"The government is afraid of putting the farmers out of business instead of letting the market float in a demand and supply situation," he said, "and it's frightening for us."

Ask Joe Rosin what he thinks will happen to profit margins this year and he will reply,"I would give a zillion dollars for the answer to that question."

Consumer buying habits also have changed, affecting the Georgetown vendors who rely more heavily on repeat customers than on the tourist trade.

"It used to be a woman would choose six scarves, lay them on the table and say how much," said Peter Wood, a three-year veteran of street vending who sells brightly colored fans, scarves and parasolas imported from the People's Republic of China.

Though he has raised his prices by perhaps 5 percent over last year, Wood says he is deeply affected by the inflation that has cut into luxury spending.

"Now," says Wood, "they examine the merchandise, ask how much and buy two."

Wood has also found he has had to alter the goods he sells to suit the needs of a clientele he is trying to establish. He used to sell high quality merchandise such as imported leather ladies pocketbooks.

But he said, "I just wasn't getting a high volume of sales, so now all I sell is junk."