NEW YORK (CNN/Money) - This week, one of golf's biggest events takes place: the 2004 United States Open. The storied, 110-year-old tournament has become almost as much about commerce as about sport.

Fortune.com • So you want to join Shinnecock?

During the Open, which ends Sunday, more than 50,000 spectators a day will roam the grounds of the Shinnecock Hills Golf Club, on the Gold Coast of eastern Long Island, N.Y. They'll spend a lot of money while they're there.

Retail operations at the four-day event have become a big business. The Open's version of the souvenir stand is a huge tent, a mini-mall really, filled with tons of golf-related goods. ESPN reports that the United States Golf Association (USGA), the governing body of the Open, expects to sell $10 million worth of merchandise at Shinnecock.

Apparel is big here, according to Dave Matyasovsky, one of merchandising staff. The stock includes 100,000 hats alone. There are shirts available from Ashworth, Polo, Nike, Tommy Hilfiger, and Bobby Jones at prices ranging from about $50 to $150. U.S. Open branded towels can be bought for $14 and umbrellas for $22.

Matyasovsky says he himself owns a Shinnecock Hills blanket ($30). Other popular items include golf prints and paintings, priced from $25 to $1,300.

Golf balls from Calloway, Nike, and Titliest go for $10 for a sleeve of three. The cheapest item for sale is probably a U.S. Open brass ball-marker for $2.

Many spectators at Shinnecock will come as pampered guests of corporate sponsors. (The USGA declined to release any information on the identity or number of companies involved.)

Susan Nieman of Ridgewells, the Washington D.C.-based caterer providing meals for the Open, says there are 56 hospitality tents scattered around the course to satisfy the food-and-drink-related desires of corporate guests.

"For breakfast, we have granola, yogurt, Belgian waffles, fresh Canadian bacon, muffins, bagels and lox, and more. At lunch we serve beef tenderloin, roast loin of pork, crab cakes, a dozen kinds of salad, lamb, several kinds of chicken breasts," says Nieman. "Our concession to the New York venue is pastrami and corned beef sandwiches and Long Island duck salad."

The firms hope to help grease the wheels of industry by hosting clients in lavish style. The fortunate few will have their tickets, meals, and many souvenirs given them free of charge. If they come from outside the area, they're sometimes put up in luxurious rental houses for the week or in the limited number of hotels available in the fashionable Hamptons locale, which often charge upwards of $300 a night.

Ridgewells says it will serve nearly 15,000 people a day during the tournament.

So many people want to see the Open that the USGA sells tickets, which cost $85 each this year, by lottery. The drawing for this year's Open took place in late August 2003. Information about how to apply for the 2005 tournament is available on the USGA Web site. Applicants must file between June 21 -- that's Monday -- and August 15.

Of course, last-minute golf fans can always get resold tickets. Many are available for the rest of this year's tourney through Web sites such as TicketCity.com, which is currently advertising tickets starting at $95. (Expect to pay more than that, though.)

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If you buy your own ticket, you're on your own as far as procuring food. The concessionaire for the Open, Prom Catering, has 12 separate concessions on the course grounds, and Prom's president, Bill Given, says his company will provide meals to nearly 50,000 people a day.

In addition to the 12 food stands, which offer standard concession foods such as hot dogs ($4.50) and hamburgers ($6), Prom has a 30,000 square foot tent for what's called Trophy Club customers, where it sells more upscale products such as half-pound burgers ($8.50) and corned beef or pastrami sandwiches ($8.50).

Given says the USGA "is very sensitive to pricing. They want to keep the whole spectrum in mind." That means the prices on Given's goods tend to fall well below those of other sporting events in the area. "We sell a 16-ounce draft for $4.50, and an imported one for $5.50," he says. "That's more than a dollar less than at Yankee Stadium" in both cases.

Given worked his first tournament in 1970. Even in the last 10 years, he says, "the merchandising aspect of the Open has doubled in size." He believes corporate hospitality has swelled about 30 percent over the same period.

With every other aspect of the Open growing it's apt that the prize money for the tournament has grown as well, reaching a total of $6.25 million including a first-place purse of $1.125 million.

It's all a far cry from the first U.S. Open in 1895. Back then, spectators watched for free and the winner took home $150.