At long last, we know what price glory.

Actress Tuesday Weld pegs it at $15 million in her suit against the makers of her new movie: "Who'll Stop the Rain." Pretty-boy rock star Peter Frampton would settle for a modest $10 million in his suit against the producers of "Sgt. Pepper's Lonely Hearts Club Band."

The hassle is over star billing - whose name gets played where and how big and in what order and color and typeface, and so on in a Machiavellian tangle that nowadays has come to consume more time in Hollywood than haggling over million-dollar salaries.

"Nothing is more sacred than the billing clause," says Elliott Hoffman, who is Frampton's lawyer. "It's the hardest to negotiate." With the added twist, as one Warner's executive points out, that "you can lie about how much money you got to play a part, but everybody knows what your billing is."

Billing clauses took up five pages of Weld's contract for "Who'll Stop the Rain," for instance. She was to get billing following star Nick Nolte, above the title of the movie, and in type as big as Nolte's. The only exception was to be an "artwork" title, in which names might be woven into the background or given other "fanciful use," as in the puppet figure in the title for "The Godfather."

It all seemed so obvious, which is why Tuesday Weld hollered for super-agent Sue Mengers when the first ad appeared. There was Nolte's name, far bigger than hers, alone over the title. Mengers dialed United Artists. If they changed the ad, then and there, she said, there'd be no problem.

"Tuesday has worked long and hard to establish herself as one of the foremost actresses in this industry," says Mengers."If Tuesday didn't get costar billing in this picture, why would anybody else give it to her for her next? Billing is as important as money in this business. Money is predicted on billings. Is she a Streisand? No. But Nick Nolte isn't Steve McQueen, either."

All hopes for a quick kiss-and-makeup were dead for sure when producer Herb Jaffe declared it was all a matter of "interpretation."

"She knew there was a costar billing with an artwork exception," Jaffe says. "And it is an artwork title. But she is costarred on the screen."

Screen billing, at the beginning or end of a film, is different from ad billing, and there's marquee billing and radio-and-television promotional billing. Not to mention running billing, box billing, likeness billing, alphabetical billing, feature billing . . .

The question is: "Who cares?"

"Angels dancing on the head of a pin, that's exactly what it is," a studio publicist admits. "Nobody cares but people in the business."

But it happens to be a totally unpredictable business of big risks, stakes and egos. Careers can climb or crash over the size of the letters in a name.

Steve McQueen, for instance, was originally slated to play the Sundance Kid to Paul Newman's Butch Cassidy. Twentieth Century-Fox could see a big billing battle coming, so their artists devised a flipping card which when see on screen, flashing from Newman to McQueen to Newman to McQueen, would keep everybody happy. Except McQueen was still unhappy. And the producers had to fall back on a lesser known - Robert Redford - who got lesser billing for the last time in his career.

In "Harry and Walter Go to New York," four egos had to be assuaged. The result was that Diane Keaton, Michael Caine, Elliott Gould and James Caan had their names billed in a specially designed diamond, aligned so that none got the edge on the others.

"Billing became more of a bargaining point when the studios ceased having actors under long-term contracts," says Dan Terrell, former vice president for advertising at Metro-Goldwyn-Mayer.

The breakdown of the contract system meant that each movie entailed separate negotiations, which meant that agents were suddenly crucial and powerful, fighting for big money and billings.

Lest agents be given all the blame, however, Terrell points out that Cary Grant always drew up his own contracts, giving MGM "the wildest problem that confronted us. He had it in his contract that no one's name could be longer than his in ads. In 'North by Northwest,' his leading lady was Eva Marie Saint, who had it in her contract that her name had to appear in a certain height. Without compressing her name, we had to stretch the lettering in Grant's name so that it became longer without looking awkwardly elongated."

Once, of course, billing was simple. You were a star or you weren't. Then, when the Age of Agents came in, back in the '50s, new and wonderful inventions appeared.

Suddenly, last billing became alluring, if the name of the actor was preceded by the word "and." Even better, it should read, say, "and Mel Brooks as "Tikon,'" as it did in the ad for "The Twelve Chairs." In that ad, Brooks also grabbed a totally individual typeface, and had his name inside a box, which set him off from Dom Deluise, who was given a parenthesis reading "(TV's brilliant comedy star)."

Similarly, Judy Garland demanded, and got, last billing in "The Diary of Anne Frank," in a box, with the name of the character she played.

Epics and spectaculars such as "The Longest Day" or "Earthquake" or "A Bridge Too Far" required so many stars that the only solution was to list them alphabetically, then pay supersalaries to the superstars, such as the $2 million Robert Redford got for five weeks work on "Bridge."

But in "Around the World in 80 Days," Mike Todd found his way around this problem by giving David Niven and Cantinflas top billing and all the cameo stars alphabetical billing - plus individual film-clip portrait credits flashed on the screen (alphabetically, of course) at the end of the movie.

The supreme billing nowadays, according to Elliot Hoffman, who is Peter Frampton's lawyer, is the "is" billing.

"Like in 'Paul Newman Is Hud,'" Hoffman says. "And alone above the title, of course. "If the name of the movie had been different, I would have asked for that for Peter. But we couldn't very well have it: 'Peter Frampton Is Sgt. Pepper's Lonely Hearts Club Band,' could we?"

What Hoffman got originally for Frampton, he says, was his name, alone, above the title. "Then the contract was modified to put the BeeGees above the title, but on a separate line, below Peter Frampton."

When they appeared on the same line - even with Frampton's name to the left, which is preferred because people read left to right - Hoffman got a judge to issue a temporary restraining order, putting Frampton's name back on top.

Also, says Hoffman, everybody's a star, nowadays. "The director, like Robert Altman, or a producer, like Dino de Laurentiis; they want top billing too."

Well, of course, Doesn't everybody?Don't you think that presidents and premiers count the number of guns that go off in those salutes? Protocol chiefs exist to ensure that proper ranking is maintained at official functions and dinners - where the equivalent of the title has always been the salt - you're either above it or below it. British peerage has its Debrett's, newspapers their mastheads, privilege its rank. These things are serious. They establish who you are in terms of everyone else, and what other test is there?

"In this industry," says Sid Sheinberg, president of Universal Pictures, "billing is preceived as a level of achievement - a symbol of where you are in the business."

"Bank credits still beat screen credit," says Peter Guber, producer of "The Deep." "But in the microcosm that is Hollywood, money and billing are the going currency."

But for all the reverence and brouhaha, no one has ever calculated exactly what billings are worth, a thought not lost on Elliot Hoffman, in the "Sgt. Pepper" fracas. "It's never been evaluated. What you have to find out is what the star would have taken to give up his billing."

Mike Medavoy, now executive vice president at Orion Pictures, but who was with United Artists when the original package for "Who'll Stop the Rain" was put together, says that the problem is not apt to amount to much "because if you do sue, it's very difficult to prove damages."

This attitude may reflect what Chester C. Migden, head of the Screen Actors Guild, calls the "sue me" syndrome. When faced with a complaint, the producers would "remind the player that the studio had lawyers on retainer, and that maybe he'd have a hard time finding work after this." (Though Medavoy says: "I don't think what Tuesday is doing will affect her career one way or the other.")

In the past, numberless billing disputes have been settled by the placing of a small advertisement in Variety or other trade papers, informing their small but passionate readership that actor X should have been credited bigger in movie Y.

In the making of "F.I.S.T.," star Sly Stallone and screenwriter Joe Eszterhas were trading bar-fighter taunts through the media, when story and writing credits started wavering in Stallone's favor.

Said Ezstehas, in Esquire. "I could go 10 or 15 rounds with him and win."

Said Stallone: "He just has to name the time and place."

But when the movie opened in Los Angeles, Eszterhas and Stallone were both there to make up with, literally, a hug.

Finally, the monster lawsuits may be irrelevant anyway. In July 1977, the Screen Actors Guild signed a new contract providing for arbitration for all billing disputes - the only problem being that in more than a year, no one has invoked it.

Maybe it's just too much fun to do it the old way.