It's six o'clock on a Friday night. You have a date for the movies. But the only new ones playing are "Hardbodies," "Piranha II," "Making the Grade" and "The Clones of Bruce Lee." What can you do?

One alternative is to rent a movie from your nearest video store. In the Washington area, this would probably be Erol's. With 28 locations, 1,800 film titles, and more than 100,000 members, Erol's Video Club is the undisputed king of local movie rentals. How the company earned its crown would make a pretty good movie in itself.

Behind the increasingly prevalent Erol's facades is an old- fashioned success story of an immigrant who came to America and struck it rich. And Erol's success in the videotape rental business make him part of one of the country's fastest-growing industries, supplying tapes to be fed to home videocassette recorders, machines that are multiplying in American homes faster than a wet gremlin.

The Erol in Erol's is Erol Onaran, a 50-year-old Turkish immigrant. When he came to this country 24 years ago, Onaran's only television experience was as a repairman in his own shop. Although he says he was comparatively successful in Turkey, he sold his business and came to the United States -- with just $32 in his pocket.

Onaran applied his trade first at Fulford's Television, then at German Hi-Fi. As Onaran tells it, he became more productive, asked to be paid on straight commission and was turned down. He and an old friend, Yilmaz Turker, then gambled on establishing an inexpensive, independent home TV repair service. In 1963 they opened their first television shop in Georgetown. Erol's continued to be moderately successful in electronics sales until 1980, when the first video movies slipped into store shelves.

"I was very unsure about them at first," says Onaran. "These films seemed almost illegal. So I made it clear they were for purchase only. Then one day I visited a store in Baltimore. They had a very good display of videos for rent. So I thought, if they could do it, I can do it. And I did."

Customers flocked to the new market. In 1982 Erol's had seven stores. That number quadrupled in less than two years as the chain expanded into the suburbs. By comparison, Erol's closest competitor, The Video Place, has eight stores.

A consummate businessman, Onaran declines to discuss his private life, but freely explains the policy that has made him a video mogul: "The customer always comes first. The suppliers come second. My employees come third. And I come last."

Onaran has had little difficulty adjusting to life in this country. He says he feels comfortable with its competitive spirit and its emphasis on individual initiative. Even in Turkey, he says, he identified more closely with his professionally direct American acquaintances than with his more casual countrymen -- a trait that proved useful as his business adapted to the rapidly changing technological market.

"In Turkey everything works slowly," he says. "It is not bad really, just different. Shops close when owners feel like it; service seems inconsistent. I had little patience for this sort of business. You could say I was more American than they were."

Onaran, who lives in Arlington, admits to being a wealthy man. Two of his sons hold key positions in the company, and Turker still assists him. Although Onaran refuses to discuss his company's financial details, he acknowledged that he has done well enough to consider expanding beyond the Washington area, possibly into Philadelphia.

The success of Erol's reflects a nationwide pattern that has placed videocassette recorders among the largest selling commodities in recent business history. Video Week Magazine says that 8.3 million Americans own VCRs, putting the machines in about 10 percent of the country's households. The percentage is even larger in the Washington area, where only an estimated 15 to 20 percent of television households have access to cable. In Washington itself, Home Box Office and Super TV offer the only alternatives to over- the-air channels, and Erol's seems to have benefited greatly from the lack of viewer choice.

According to executive vice president Curtis Woodard, Erol's store in Arlington -- an area that does have cable -- took longer to grow than stores at other locations, but now handles comparable business. However, Woodard says, Arlington patrons tend to rent fewer videotapes per visit, a trend that may spread with cable.

"It (the arrival of cable TV) may have an immediate effect of slowing down business," said Woodard. "But cable repeats the same things too many times. Eventually they will come back to us."

Onaran attributes his company's early predominance in local video rentals to computerization. His stores have converted from cash registers to computer terminals, and each customer's membership card contains an individual computer bar code that electronically records all movie returns and withdrawals. The system allows for easier inventory control as well as rapid customer service.

Newer Erol's locations handle only video rentals, which remain comparatively inexpensive. Members pay $15 for a half-year's subscription, $25 for the full year, and $69 for lifetime membership. A first-day videotape rental costs $2 per film, each additional day $1. Discs, a fading video format, cost slightly less. The chain offers occasional discounts on membership and rental costs.

Erol's divides movie selections into 17 categories: drama, adventure, comedy, horror, science-fiction, mystery, classics, foreign films, children, educational, martial arts, mature theme, sports, rock, musicals, westerns and some foreign movies, including, appropriately enough, Turkish films. Conspiciously absent are the X-rated features found in many other rental places.

"It's a matter of our being a family-oriented company." said Onaran. "People can come in and take anything off the shelf and not be offended. But I'm a businessman. If people were to tell me they would like the other kind, well then I would get them."

Even without X-rated movies, the size of Erol's inventory represents the chain's biggest advantage over the competition. New releases disappear quickly -- "Terms of Endearment," which won an Academy Award for Shirley MacLaine in April, was available for rental by June -- and the chain maintains a fair selection of durable older films. The Onaran policy seems as simple to state as it is difficult to carry out: Try to please everyone.