Consumers are increasingly turning to the Web to compare medical fees as the economy and less generous health benefits squeeze household budgets.

Shopping around for lower-priced medical care has never been easier. More than 30 states have passed laws that require online publication of medical fees by hospitals and other health care providers.

But combing through often confusing and overlapping Web sites set up by doctors, hospitals, insurers and state officials can be daunting. And even when patients think they know exactly what they'll be paying, unexpected fees can quickly inflate medical bills.

That's why doing the research is just the start. Patients should also ask plenty of questions to avoid surprise charges.

Rising health care insurance premiums, co-pays and deductibles, as well as the growing number of uninsured, are creating new demand for data on the cost of medical services.

Traditionally, the vast majority of insured patients had little incentive to shop around because their plans protected them from the brunt of health care costs. Of the 170 million Americans with health insurance, only 8 million, less than 5 percent, are in high-deductible plans, which require patients to pay a couple thousand dollars or more out of pocket before insurance coverage kicks in. But that figure is growing as employers look to rein in rising health care costs while still offering some health benefits.

Meanwhile, as unemployment rises, experts estimate that 50 million people lack health care coverage.

"What's driving this is that people are becoming less isolated from the cost of things," said Merrill Matthews, director of the Council for Affordable Health Insurance, a conservative-aligned advocacy group. "It's creating a market out there where consumers want to know more about price."

Patients with insurance can start their search on their insurers' web site.

Aetna Inc., UnitedHealth Group Inc., and Cigna Corp., provide cost and quality information for thousands of hospitals, doctors and clinics.

The sites allow users to compare, for example, the out-of-pocket cost of having a MRI scan at different locations. In many cases, going to specialized imaging centers will be cheaper than going to hospitals, which charge higher fees to support their considerable overhead costs.

"We've been launching a number of tools in recent years to measure cost and quality," said Joe Mondy, spokesman for Philadelphia-based Cigna. "It's almost been an arms race in the industry."