Feeling decadent, you could fill up your bathtub with Chanel No. 5 for $1.6m (800,000).

But if you want a 30-second advert during the Super Bowl, the championship of American football, it will cost almost $2.3m (1.3m).

With declining television audiences in the US, the Super Bowl is one event that can guarantee the most eyeballs for their buck.

A media event

The cost for advertising has risen dramatically in the last 38 years. In the first Super Bowl in 1967, a spot cost almost $240,000 in today’s dollars.

But there are few television events like the Super Bowl that can guarantee an audience of 140m viewers, especially with a declining network TV audience due to the Internet, DVDs and hundreds of cable, satellite and channels.

Apple has teamed up with Pepsi and former legal targets

“This is a throwback to old TV, when you didn’t have a choice. You couldn’t zap away from the commercials,” said Matt McAllister, an advertising and culture expert at Virginia Tech University.

“The Super Bowl is not just potential exposure to those eyeballs. It is exposure to those eyeballs. The idea that people channel surf at Super Bowl parties is absurd.”

And over the years, the ads have become an event unto themselves.

“The Super Bowl is something where the ads are covered as news themselves,” said Mr McAlister.

They are the only event in the TV year where the ads are previewed, and then critiqued on the morning news shows after the Super Bowl.

“Even the flop ads get free air time,” Mr McAlister said.

Cultural icons

The tone of the ads over the last few years have been more sombre following the attacks of 11 September and the lead up to war in Iraq.

But, back this year is the irreverent tone that has made many of the ads cultural icons.

This year, Pepsi and Apple Computer will be poking fun at online music file traders.

Pepsi will be giving away 100 million from Apple’s iTunes music store, and the commercial features 16 teens who were sued by the recording industry for illegally music.

The ad is set to punk band Green Day singing, “I fought the law (and the law won).”

An ad for office supply store Staples features a worker who rebels against an office supply clerk who demands pastries in exchange for folders and paperclips.

Instead of going through the supply clerk, he buys his supplies at Staples and with the help of some mobster muscle demands a pastry in return.

Politics-free zone

But in addition to humour this year, election year politics has tried to invade this perfect advertising environment.

Networks banned ads that poked fun at the president

The CBS network rejected ads from political activist group Moveon.org and from People for the Ethical Treatment of Animals (Peta).

The Moveon.org ad criticised President Bush for the ballooning national deficit, and the Peta ad promotes vegetarianism with the message that eating meat can cause impotence.

CBS rejected both ads on the basis of its policy against advocacy advertising, saying the policy was designed to prevent those who can afford advertising from having an undue influence on “controversial issues of public importance.”

Washington Post media critic Howard Kurtz said in an online discussion that the networks’ prohibition against advocacy advertising applies to everyone.

“When some group gets its ad rejected by ABC, CBS or NBC, it cries foul and political bias and censorship. But everyone in the issues realm is basically shut out,” he said.

But Peta spokeswoman Lisa Lange said: “CBS not only takes advocacy ads, but has shown them during the Super Bowl, including Truth.com anti-smoking ads and anti-drunk driving ads sponsored by beer companies.”