ARTHUR Ringwalt Rupley IV, in Ralph Lauren polo shirt, black chinos, butter-soft black leather jacket and Yves St. Laurent apre s shave, sipped a margarita and said, with a smile, "As far as marriage and money, I've reached the ultimate."

Two weeks ago, the 22-year-old Rupley, reportedly the wealthy heir to a Fairfax, Va., real estate fortune, married 42-year-old jet-set divorce' Soraya Khashoggi in the chapel of the circuit court clerk's office in Manhattan. The British-born black-haired beauty made international headlines when she filed a $2.5 billion divorce suit in 1979 against her former husband, Saudi Arabian oil tycoon and arms dealer Adnan Khashoggi. The suit was settled out of court for a substantial sum.

Rupley, also known as "Burke," told reporters he was worth $125 million, and in one story was quoted as saying he spent $100,000 a month. But his grandmother, Mildred G. Rupley of Alexandria, has said she limited his access to his inheritance after he accumulated a string of debts.

Mayor's Jewelers of Miami has filed suit against Rupley, claiming he owes them $250,000. At the fashionable Burdine's department store in Fort Lauderdale, Rupley's account is $10,000 overdue and has been placed with a collection agency, a store spokesman said yesterday.

Rupley also allegedly owes a Florida couple $75,000, has bounced checks with one of Manhattan's fashionable bistros and had an expensive sportscar repossessed by a Fort Lauderdale car dealer after two of Rupley's checks, totaling $17,000, bounced.

Rupley came to Alexandria last week to visit his grandmother. He said he and his bride, who Rupley said was eight months pregnant, would reunite for a honeymoon off the coast of France in early August. In a two-hour interview, Rupley spoke at length about his freewheeling life style, his obsession with spending money and his marriage to Soraya Khashoggi, reputed to be one of the wealthiest women in the world. But when a reporter began checking into Rupley's financial situation, he abruptly canceled a scheduled photo session and could not be reached for additional comment. Khashoggi could not be reached for comment yesterday.

Rupley's deposition testimony in Florida as part of a lawsuit brought by Mayor's Jewelers revealed that he spent $1 million of his family's money, including $25,000 in jewelry for his former girlfriend, actress Britt Ekland, and now lives on an allowance of $3,000 or $4,000 a month.

But Rupley said in the interview that he did not marry Khashoggi for her money.

"Everybody looks at her because of her money. She appreciates me because I don't look at her money."

He said he loves Khashoggi for her beauty. "Looks mean a lot to me," he said. "For 42 and eight children, she's absolutely stunning."

He said he met Soraya Khashoggi 18 months ago at a party, through her 20-year-old son, who was friendly with young Rupley.

They married July 13. It was, he said, a spur-of-the-moment thing. "We got married and didn't speak about it for the rest of the day. That's what I like about her. She's so casual."

He brushed his auburn hair from his forehead. His face was pale. More fashionable-looking than handsome, he is tall and thin with a punk-style haircut, gold band on his left hand and a gold cross around his neck. A gift, he said, from his new bride.

"I'm doing too much too soon," he said. "It kinda scares me in a lot of respects. It's kind of the feeling that I've done everything. A lot of people were shocked when I married Soraya, that I wasn't on to the next one. I'm a very flighty person.

"If somebody comes up to me and I find her more exciting than Soraya, well, that's the way it goes. Soraya knows this. She knows she has to keep me happy.

"A lot of people think I went out with Britt and married Soraya for attention. That's not true," he said. "Although I love the limelight. There's no question about it." Credit Lines

Rupley, according to a deposition he gave in the Mayor's lawsuit, was born in Kansas City, Mo., in 1960, the son of Mildred Tyler Rupley and Robert English. Family lawyer James Arthur of Alexandria confirmed that Rupley was raised by a Florida woman, Mary Westerburg. Mildred Tyler Rupley, 44, now lives in Alexandria with her mother. Rupley grew up in Florida, attended public school and dropped out before graduating to live in New York, he said in his deposition.

At about this time, he began receiving large sums of money from his grandmother, who was widowed in 1977.

Rupley has said his grandfather, Arthur Rupley Jr., was a real estate magnate and a multimillionaire. Fairfax County probate records indicate that the grandfather left an estate in Virginia valued at approximately $700,000. Half of the estate went to his widow. The other half was to be divided between Mildred Tyler Rupley and her son, Arthur Ringwalt Rupley IV.

According to James Arthur, the family lawyer, Mildred G. Rupley owns an apartment building in Harrisburg, Pa., a few parcels of land in Rhode Island "not worth much," two apartments in Fairfax County and a small piece of land in Richmond. Two years ago, the Belle View Apartments--of which Mildred G. Rupley owned 27 percent--were sold, reportedly for $23 million.

Young Rupley--who sometimes went by the name Arthur English--was given money by his grandmother "as needed," he said in a deposition. He spent $650,000 to "support his life style," he said, and estimated that between 1979 and 1981, he spent $1 million on jewelry alone. Among Rupley's purchases was jewelry bought at a Hawaiian resort for Ekland, he testified.

Rupley's statements are contained in a lawsuit filed by Mayor's Jewelers, which claims that Rupley still owes $250,000. According to Rupley's Florida attorney, Rupley denied purchasing some of the items and questioned the total amount. Among the items Rupley allegedly purchased were a $34,000 Rolex watch, a $9,900 pair of earrings, a $7,000 necklace and a $1,000 pen-and-pencil set.

Henry San, director of credit for Mayor's, said in an interview this week that Rupley used a Nov. 17, 1980, New York magazine article to gain credit at the store. The jeweler said the young man--who already had an account with the store--showed a photocopy of the article to store personnel to have his credit line increased. In the article, Rupley is quoted as saying he was worth $125 million and that he was planning to build a $10 million hotel in Greenwich Village. "Someday I'll be like Helmsley and the rest of them," Rupley was quoted as saying. Sharon Churcher, author of the article, said this week she became concerned after details of Rupley's background did not check out. Immediately after the story ran, she said, "We got calls from all over the country from people telling us he owed them money."

In June 1981, a Florida couple befriended young Rupley and were impressed by his big spending. "He spent money like it was water," the man recalls. "He represented himself as a millionaire, renting yachts and all that. One day he asked us to lend him some money for a short while. We lent him $75,000."

The two said in a telephone interview this week that they have made numerous unsuccessful attempts to get the money back, although they said Rupley sent them a check recently for $750.

Dennis Deskovic, owner of the Car Exchange in Fort Lauderdale, said Rupley purchased a 1979 Jaguar nine months ago, claiming to be a millionaire. "He was very suave about it."

Deskovic said Rupley gave him two checks, totaling $17,000, which bounced. He said he contacted Rupley, who assured the owner he would come in with the money. Deskovic said he repossessed the car 10 days later after a telephone conversation with Rupley's grandmother.

"She just said he was cut off from any funds, that he had squandered an enormous amount of money and that he was just very flaky," Deskovic said. "The guy's a total wipeout."

Mildred G. Rupley has declined to be interviewed, saying her grandson must "speak for himself."

On July 5, 1981, The Miami Herald published an article on Rupley titled, "Poor Little Rich Kid? Not He." Written by staff writer Cathy Lynn Grossman, the story said Rupley dropped $100 tips, rode in limousines and lived like a king in Manhattan.

One paragraph in the story said, "At least $125 million of his money is knotted up in trust funds and heavily taxed, he says. Young Rupley must restrain himself with an allowance of $80,000 to $120,000 a month, he says."

One of Rupley's favorite Madison Avenue bistros, Le Relais, was stuck with several bad checks, according to owner Albert Hacko. Another restaurant employe said Rupley promised to make good on the checks, totaling several hundred dollars, but never did. "You can't make a scene in a restaurant," the employe said.

Rupley also told The Miami Herald that Arthur Rupley III--who died of cancer at the age of 33--was his father. But according to Fairfax County probate records, Arthur Rupley III was Burke Rupley's uncle, who died without a will, leaving an estate in Virginia of $20,000.

In the story, Rupley also was quoted as saying that the woman who raised him, Mary Westerburg, lived in Florida's exclusive Lago Mar Country Club.

According to Henry San of Mayor's Jewelers, Rupley used that article to gain credit in the Fort Lauderdale area.

"When that came out, he just had a field day," San recalled.

But when creditors began calling Rupley's grandmother, she became annoyed and cut her grandson's allowance to $3,000 a month, according to her deposition in Mayor's lawsuit.

Rupley, in a deposition given last September, complained of his plight.

"It's just not right what she has done to me," he is quoted as saying. "She's left me right out in the cold, not only financially, but all the way around. You just can't leave somebody with those bills and expect them to survive."

However, Mildred G. Rupley testified that she paid her grandson's $25,000 American Express bill. He testified that his $100,000 Fort Lauderdale apartment had been foreclosed on and that a Florida interior decorating firm was still owed $12,000.

Rupley also said in the deposition that the $125 million figure in the New York article was false and that he had lied when he said Mary Westerburg lived at Lago Mar.

It was around this time, friends say, that Rupley stopped dating Ekland and started seeing Soraya Khashoggi.

The two posed for photographers when Khashoggi's daughter Petra was christened last year. Although Soraya Khashoggi at first refused to name the father of her illegitimate child, she later said that it was Winston Churchill, member of Parliament and grandson of the late prime minister, with whom she claimed to be romantically involved for the past five years.

Arthur Rupley told reporters he was the godfather.

A family friend, who did not wish to be identified, said, "I think he lives in a dream world." Supersalesman

Sitting in an Alexandria restaurant, Arthur Ringwalt Rupley IV--lover of limos, dancer of discos--summoned the waiter for another drink.

"I'm into having a good time. My grandfather made a lot of money and didn't enjoy any of it. I spent $100,000 in one day," he said. "It's my favorite thing. I love to spend money. It's an obsession with me."

Neighboring diners strained to hear his next confession.

"There are so many things out there I still want. I want my own yacht. I don't mean with Soraya. I mean my very own."

His only problem, he said, was losing things. "I lose one watch a month," he said.

He pouted, momentarily bored with the conversation. He cut his chicken into tiny bites, all at once.

"She Khashoggi wants somebody to tell her what to do," he said. "She doesn't want to make any more decisions in her life. Who wants to go into a marriage with a woman with THAT kind of money and have her rule you?"

Asked if the child Khashoggi is carrying is his, Rupley said, "Maybe it is, maybe it isn't." Later, he said the child is his, and will be born on the yacht, which is equipped like a mini-hospital.

"I find that very exciting," he said.

If anything will tear them apart, he said, it will be her children. They don't like him, he said. "A lot of people don't like me. They don't like what I stand for."

Her former husband, Adnan Khashoggi, he said, "is very upset, by the way. I think he may try and stop this. He would try and buy me off. I think he's still very much in love with her.

"I'm not afraid," he said. "But people tell me I should be."

He doesn't know what makes him attractive to older women.

"I always thought with Britt it was money," he said. "I've thought a lot about that question. Especially with Soraya. There are so many young men she could have had. Maybe it's just me."

His new bride, he said, has written her autobiography and hopes to publish it soon. They're also talking major motion picture, he said. "Soraya wants me to be the producer."

But if it all ended tomorrow, he said, he could still sell cars.

"I can sell anything," he said.

Especially Arthur Ringwalt Rupley IV.

"That's right," he said. "It's all it takes. If you sell yourself they forget what they're buying and they buy it."