What do the Kennedy Center and Sheik Yamani have in common? The average price of a ticket to the Vienna opera is the same as a barrel of O.P.E.C. crude about $24.

Even at that rate, the Vienna Opera's dates are virtually sold out, leaving standing room only.

So every day at 10 a.m. (noon on Sundays) the Kennedy Center will sell 50 standing-room places for that night's performance at the low price of Saudi crude before the last Arab-Israeli War -- $4.

In Vienna, the opera's home, the unseated opportunities are much greater and the charge much less. There, 600 standing-room tickets are available -- their cost tied traditionally to the price of bread.

A scene from 1977 in Vienna: We want to see the opera this night but as usual it is sold out. Along towards 5 o'clock -- fortified by things to munch and read -- we join the line at the side entrance of the Opera House. The line is already long, filled with cosmopolitan opera-goers and groggy tourists.

On one side of us two chaps are talking about the latest big soprano in Bulgaria. On the other side of us an American kid wakes up from sunny dreams of the Big 10 to find himself in cold, damp Vienna in a line with no end in sight.

"Are we going to get in?" he asks me.

"Does Vienna have Wienerschnitzel?" says I.

All the while these chubby old guys in brown uniforms are policing the line with an exquisite, jolly nastiness that seems uniquely Viennese. One American complains that "Those guys are worse than the Germans!" (Sure kid, but take the price of a loaf of bread to your usual German opera house and try to get in.)

The guards try to keep the opera house a bit more orderly than a train station, and one does not sprawl out in sleeping bags at the Vienna Opera. Sometimes they let you sit on the floor, sometimes they make you stand. Sometimes they tell you the line will move in a half hour, and then five minutes later it surges forward only to wait at another locked door. It seems that the guards delight in casting calculating glaces at Americans, as if to say, "You can only get in, barbarian, if you can recite the first three arias of the night from memory."

The line surges forward one more time, and in a matter of minutes we are at the ticket window -- after a good two hours. The opera will not start for an hour or so, but the guy in the ticket booth rips the tickets out like the express to heaven was leaving in three minutes.

There are two standing places at the Vienna Opera. About 150 of them are behind the orchestra seats. At 85 cents each, these afford an excellent view of the action: I saw Agnes Baltsa singing Romeo in Bellini's "I Capuletti ed i Montecchi." Her voice was magnificent, but I fell in love with her thighs. (Try that at an American standing-room place.)

Vienna's second standing-room area is up in the rafters. But they are roomy rafters, and tiered so that there is no trouble seeing over gangling American tourists who happen to get in front of you.

From that vantage point, I heard Birgit Nilsson and Leonie Rysanek sing, and I swear their voices seemed to dance a few feet in front of me -- for about 60 cents.

But first one has to get there. After we get our tickets, we still find ourselves confronted with another line that forms along stairs that lead to another locked door. On big nights, this is a disordery line, on really big nights it's not even a line, it's a pulsing knot of opera history.

In 1875, a 15-year-old music student named Hugo Wolf was in the "line" to see Wagner's "Tannhauser" while the Master himself sat in the boxes. Wolf wrote to his father about it:

"There was such a frightful scrimmage that I was worried about myself. I wanted to back out, but it was already impossible, for no one near me would make way . . . At last the door was open, the whole crowd pushed their way inside, and it was fortunate that I was drawn into the middle, for if I had got to the side I would have been crushed against the wall . . ."

The scrimmage still goes on. One dashes up the stairs to a standing place and ties a hankerchief around the pole to claim a spot. Then, since the opera is almost an hour away -- one can waltz about a bit and be snooty -- just like the other opera-goers.