Through the grill I could see, but not hear, the cashier mouthing the price for two adult movie tickets. Could she really have said, "Ten dollars, please?"

Her finger wiggled under my nose and pointed up to a sign high in the window: $5 Admission For This Show.

"Outrageous," I huffed through the grill, as behind me dozens of feet shuffled impatiently.

"I don't want to buy the seat, just rent it," I insisted through the glass.

Her finger pointed again, this time inside toward the kindly looking man in a rumpled, shiny suit taking tickets from patrons entering the dark--and expensive--interior.

"See the manager," she mouthed.

One thing was certain, our afternoon lark of catching a movie was going to cost plenty. Seats, $10; popcorn, $1.50 for one small box; orange drinks, 80 cents each for two small cups; one chocolate bar, $1.35. Our simple spur-of-the-moment bid for Sunday-afternoon escapism was going to top $14.45 for two of us. Not a devastating blow to our budget, but a wallop to the wallet we didn't expect.

"I've had it and I'm not going to take it any more," I hissed as we strode smugly off, thumbing our noses at inflated theater prices.

"Why is it," asked my wife, "that the newspapers don't list prices for the movies? Wouldn't that spur competition, maybe start a price war?"

"Yeah," I said, "and how come all the movies charge five bucks these days?"

On we went, pilloring the movie houses, government, the newspapers and even poor Dustin Hoffman, now playing in the darkened hall without us.

There must be, I thought, a better way to buy a movie. In the next few days, after phoning all 13 theaters then showing "Tootsie"--and virtually every other movie house--we found there is. Despite the confusing pricing systems, we learned that we could have reduced our cost of seeing "Tootsie" to $2, or a 60 percent reduction of the price we stalked away from.

The trick, it turns out, is the most elemental consumer lesson: Shop around.

Says Ron Goldman, president of the 30-screen K-B Theatre chain, "The cost for a movie like 'Tootsie' varies enormously, depending on location, time of showing, how you buy your tickets and some other not-so-subtle variables."

Location is the most obvious factor, says Goldman, noting that Virginia moviegoers consistently pay lower prices than those in the District or Maryland.

"I'm not sure of the sociology involved," he says, "but Virginians won't pay what goes down in Washington and Maryland. Consequently, you'll find that even the biggest hits there sell for only about $4, while Maryland and D.C. theaters charge $5 and sometimes more for the same picture."

Even though all theaters pay the moviemaker the same for showing "Tootsie"--about 90 percent of gross-ticket revenues--some of the price disparity, of course, can be attributed to the difference in rents paid by city theaters and their suburban rivals, the cost of help, even utility rates.

Still, observes Goldman, "You've got to ask yourself if it's worth the drive to Springfield or wherever to save a buck on 'Tootsie.' "

The second variable is the most complex: Movie prices go up and down depending on the hour, day and time of year you buy a ticket.

"There's no doubt about it," says Norm Falk of the 27-screen Roth's Theatre chain, "that a careful shopper can find prices cheaper at certain times. Like the airlines, theaters make most of their money at certain peak times when demand--like Friday, Saturday and Sunday evenings--exceeds capacity."

Most suburban theaters discount their matinees and first show of the evening to the $2 range for adults; some downtown movie houses do something similar for their first show on selected week days.

Because theater operators try to bring in people during slack periods, prices generally are lowest Monday through Thursday.

"The consumer, of course," acknowledges Falk, "must plan ahead just a bit to take advantage of this. You've got to phone around, check the papers and maybe keep a chart on the refrigerator of what you want to see and how the prices fluctuate.

"It's impossible to list these prices in the papers because they change all the time. But most theaters nowadays have taped messages that include time and prices of discounted seats, so you can phone ahead and get a full report."

The most intriguing cost-cutters, probably least relied upon by moviegoers, are the movie houses' advance purchase programs. Identified by many different names, they at first glance seem confusing and unappealing with their restrictions and requirement of advance payment: Who, after all, wants to buy movies months in advance?

"But the advantage of utilizing these systems," declares Michael Clark, program director of the Kennedy Center's American Film Institute, "is that you can reduce your seat price, even for prime-time showings, to the $2 range in most theaters. Since most plans call for your buying $100 to $200 worth of tickets in advance, it may seem out of reach for the average filmgoer.

"But it's my experience that most film buffs in Washington easily spend that much and more in a given year. And if you can't spring for the $100 yourself, perhaps the thing to do is pool your money with neighbors or people in the office, your club or church group. Anybody who is interested in knocking down the price of moviegoing."

Another cost-cutter recommended by Channel 9 movie reviewer Davey Marlin-Jones: Scour the pages of newspapers for films offered by colleges and universities, churches, social clubs, fraternities "and all manner of odd-ball groups.

"While these films are rarely first-run," says Marlin-Jones, "they nevertheless are always cheap--in the $1 price range--and are usually rare numbers you'll never see in the commercial houses. Sometimes you'll find an astoundingly good film that'll knock your socks off."

"Of course," he adds, "pound for pound the best buy in the Washington movie market remains the Circle Theater. They book no garbage. They know how to pair double features . . . and if you buy their advance seating plan, the prices are absolutely rock bottom at $1."