Microsoft is hoping to lure shoppers away from Google and Yahoo with a money-back scheme covering products purchased through the comparative shopping feature on its Live Search website in the US.

Consumers will be refunded a percentage of the price of eligible products, denoted by a gold coin icon, that have been purchased through the site. The scheme, which was launched this week, was inspired by a similar site that was purchased by Microsoft last year.

For example, a search for a 4GB flash memory SD card from SanDisk showed a rebate of $2.12 (£1.06) offered by a retailer for a card priced at $52.99 (£26.50).

So far, the cashback option will only be available to US citizens. Shoppers must set up a Microsoft cashback account, where the rebate money is held. When the amount reaches $5 (£2.50), Microsoft will either mail a check or transfer the money to a PayPal account or bank account. The rebate money is not released until 60 days after the purchase date in case the item is returned.

The cashback program offers an advantage for advertisers in that they only have to pay when they sell an item, known as a 'pay-per-action' fee. It also avoids the problem of click fraud, where bogus clicks on an ad drive up marketing costs.

With the US economy slowing, Microsoft's cashback program may be more appealing to advertisers with smaller budgets who only want to pay for completed transactions rather than for click-throughs from Google ads, said Mike Davis, senior analyst for Ovum in London.

"The Microsoft bit will potentially be more attractive to people with less money to spend," Davis said.

The cashback feature also thrusts Microsoft into an online retail market where it could potentially affect businesses such as eBay and, Davis said.

"Persuading people to change search engines isn't easy, since people tend to stick with the one they're most comfortable with," said Alex Burmaster, an internet analyst with Nielsen Online. "For many people, that's been Google."

But it's a step in the right direction for Microsoft despite a consensus that Google will most likely dominate the search market for at least the next two years, Burmaster said.

"I think Microsoft should be applauded for doing this," Burmaster said.

The cashback site is one way Microsoft is trying to draw interest in its Live Search engine, which ranks a distant third place compared to Google and Yahoo.

Google was used 58.4 percent of the time by web surfers in December 2007, according to data released by Comscore, which tracks the search engine market. Yahoo held a 22.9 percent share, with Microsoft at 9.8 percent.

Last week, Comscore said the number of visitors to Google's web properties surpassed Yahoo for the first time in April, at 141m. Yahoo's sites came in a close second with 140.6m visitors with Microsoft's websites coming in third at 121.2m visitors.

Microsoft's desire to boost of the popularity of its search engine also seems to be at the heart of its contentious discussions to acquire Yahoo. As of late, Microsoft is reportedly interested in buying assets related to Yahoo's search engine.