In their scruffy jeans and trainers, Ross Harper and Ed Moyse look just like any other British 22-year-olds -- except for the words 'Buy My Face' and 'Sold' emblazoned brightly on their faces.

Standing in the middle of London's shopping mecca Oxford Circus, the two Cambridge University graduates attract more than a few curious glances from the hoards of passers-by.

"How much?" a young man calls out from a gaggle of Spanish tourists, to which Harper, a former neuroscience student, replies that it's £100 ($160, 120 euros) to hire the two faces as advertising space for the day.

"A hundred pounds?" The tourists throw up their hands in mock outrage before bursting into laughter.

There may be no customers here, but others are queuing to hire the two human billboards. Harper and Moyse have made over £30,000 since setting up Buy My Face in October in a bid to pay off their student debts.

The enterprising duo plan to launch the business, which works by directing online traffic to advertisers' websites through their own entertaining site, on the international market in May.

"We've had interest from places like Hong Kong, Canada, Australia, the United States, and all over Europe," Harper said.

With record youth unemployment of 22 percent in Britain, and even graduates from prestigious universities such as Cambridge struggling to find work as the economy stalls, theirs is an unusual success story.

"We were coming up with ideas for what we wanted to do after we left university," said economics graduate Moyse. "And we thought, 'The job market's really tough at the moment. Why don't we try a creative project for a year?'"

The pair, who each borrowed £25,000 from the government to fund their studies, came up with Buy My Face over a pot of instant noodles last year while brainstorming business ideas that required only minimal investment.

"We're £50,000 in debt -- we didn't want to invest thousands more into a business," said Moyse, adding that they spent just £100 on face-paint.

Since October 1, he and Harper have managed to "sell" their faces every single day -- to large companies such as Irish bookmaker Paddy Power and accountants Ernst & Young, as well as smaller firms.

"On the very first day we sold them for £1," Moyse recalled, turning to Harper and adding: "Not a very good graduate wage, was it?"

But as word has spread about the scheme, with website traffic now peaking at around 7,000 visits a day, they have been able to command higher rates.

They currently rent their faces for up to £400 a day to advertisers, who can pay for them to complete eye-catching stunts, from skydiving to plunging into icy rivers. And they may raise prices again as their online following grows.

"The idea isn't about seeing us in the real world," Moyse explained. "It's about getting good photos and funny videos on our website, and that's seen by thousands of people every day."

In a world where successful viral advertising campaigns spread rapidly online through social networking websites, humour and creativity are crucial, explains Patrick Barwise, professor of marketing at London Business School.

"All you need to do is create something which other people will want to pass on," he told AFP.

"They're obviously very enterprising," he said of Harper and Moyse, "but I'd be surprised if it's that sustainable. Marketing is enormously faddish."

The graduates happily admit this.

"What we're doing now is a gimmicky thing," says Harper, adding that whatever its success abroad, their own face-painting days will end in September.

At that point the double act intend to set up another business, while also managing newly recruited face-painters in Britain and abroad.

"We sometimes refer to it as an entrepreneurial gap year," Harper says.

"The reason we started with Buy My Face was that it didn't require any investment. But now we've got some money to invest into another idea."

Their success may be of some comfort to other British students battling huge debts, particularly those starting university later this year, who face a controversial tripling of tuition fees.

Students who begin degrees in England in 2012 will graduate with £59,100 debt on average, according to the Push university guide.

"Students going to university now -- the fees have just risen, so they'll be coming out with about three times as much debt as we had," says Moyse. "Hopefully they can take inspiration from our story."

But the pair's parting words suggest they have a way to go before becoming dotcom millionaires.

"Could we get expenses on our train tickets?" Moyse asks hopefully.