Swiss lawyer Karael Zoller had wanted for years to take his wife and three teen-age children to the United States. As it turned out, everything fit together in 1979.

The children finally were attending the same school with the same vacation period and then there was an added bonus: Because of the steady, sharp decline of the value of the U.S. dollar, the Zollers, like millions of foreign travelers, are finding that the United States is one of the world's bargain vacation spots.

Foreigners and Americans alike have often found their money buying less in their homeland. But the continued erosion of the greenback against such currencies as the British pound, the German mark and the Japanese yen has resulted in greater purchasing power here for foreigners.

"It is much more cheaper than in Switzerland," Zoller said in heavily accented English at Dulles International Airport after a cross-country flight from San Francisco.

"We are getting mor for our money," he said. "We have paid $30 to $60 a night [for two motel rooms]. For the comparable rooms in Switzerland, we would pay $90 to $120."

For many foreigners, when it came time to think about a vacation, the dream was always to go to America. But the dream most often proved impossible. It was just too costly.

But that has changed. The combination of high prices overseas, particularly in Western Europe and Japan, and cheap air fares and tour packages has made the U.S. afforadable by comparison, not just for professionals but also for thousands of working-class people.

The dream of visiting the New World is no longer impossible.

Although Washington ranks well down the list of favorite spots for foreign tourists, nearly 68,000 foreigners entered the country at Dulles International Airport last year, a 16.6 percent increase over the previous year.

Thousands of foreign tourists include Washington on their itinerary, but airline and tour officials say that New York, Florida (especially Miami and Disney World), Los Angeles, San Francisco and the Grand Canyon are the most popular stops for foreign tourists.

More than seven out of every 10 foreign visitors to the United States still come from neighboring Canada or Mexico, but the large growth in foreign travel to America is occurring mostly among Japanese (up 18.4 percent last year to 886,447), the English (up 42 percent to 757,127), the Germans (up 31.8 percent to 485,784), the Venezuelans (up 45.9 percent to 303,948) and the French (up 20.5 percent to 259,818).

"The cost of the food is better here," English architect George McDonald said at Dulles after his transatlantic flight. "We might spend $5 for sandwiches and drinks in the airport here, but it would be $18 in England.

"Your service is better, too," the bearded McDonald added with a laugh. "That's terrible for an Englishman to say."

"We had such a good time last time [last November], we wanted to come back," said McDonald's wife, Beryl. The McDonalds and their son plan to visit friends in Hampton, Va., San Diego and Chicago on this trip.

But professionals aren't the only ones coming to America in much the same way Americans once flocked overseas.

Cosmos of London, a tour operator, started promoting low-cost, air and bus tours from England to the United States last year and designed them so they would be cheap enough for miners, truck drivers and clerks, according to Cosmos executive vice president Jeffrey Joseph.

Cosmos expected that 5,000 Britons would sign up for the trips in the first year, but three times that many did.

To help promote the no-frills tours, Cosmos published a brochure advertising that typical American fast-food meal -- a Big Mac and a Coke -- and noted that while the Coke cost the same in New York and London -- 36 cents at the time -- the Big Mac was only 99 cents in New York compared to $1.33 in London.

Cosmos' best seller is a 12-day trip to New York that costs $402.75 for air fare, hotel and some sightseeing. Another 12-day tour that includes New England, Boston, Niagara Falls, the Pennsylvania Dutch Country, Washington, Philadelphia and New York runs $582.

"The amazing thing is that these people go into stores and buy out the place, especially clothing, dresses, sweaters and suits. They come here with empty suitcases," Joseph said.

"It's just like we used to do in Europe 15 or 20 years ago," he said. "Now we go there and shudder at the prices."

Cosmos plans to sell the low-cost tours throughout Western Europe next year and expects 50,000 people may make the trips to America.

Airline and travel executives say that people of different nations like different parts of the United States. The English often travel through New England, while the Germans like camping trips in the West. Japanese tourists often prefer the western cities and like to stay in preplanned groups, apparently because of the language barriers. Germans, on the other hand, are more likely to strike out on their own in a rented car and fend for themselves regardless of whether they speak English, tourist officials say.

Almost everyone seems to want to see the Grand Canyon and many are fascinated by the mystique of the American cowboy, perhaps because they have seen so many movies and television reruns overseas.

But there are other attractions as well for foreigners. Herman Neuenhagen of Kassel, West Germany, came to the United States to visit his niece, but he also plans to stop at the casino at Atlantic City. An Englishman, Leonard Goodwin, 73, and his wife are celebrating their 50th wedding anniversary in America along with their daughter and her husband, who are celebrating their 25th, and their children.

They normally might have gone to the Spanish island of Majorca to celebrate, Goodwin said. But with the devalution of the dollar and because they had such a good time in America on a previous trip, he said they decided to come back and see the Blue Ridge Mountains, Niagara Falls, Washington, Miami and Disney World.

While the English obviously have no language hurdle to overcome in the United States, many of the other new foreign visitors who don't speak English have a difficult time coping with an American society that has done little to try to accommodate them.

When Giorgio Barbutto and his family arrived from Italy for a vacation in Washington, many of the things that could go wrong on their first day, did indeed go wrong.

Their rented car was towed away, they spent hours trying to find one of the few banks here that exchange foreign currency and they were repeatedly turned away from visiting the White House because no one they asked could explain to them how to get the free admission tickets.

Barbutto, who said he has traveled extensively, noted through an interpreter that "of all the cities in the world I have been to, Washington is one of the toughest to crack. Unless you only want to stay close to the Mall, things are not easy."