Here's a question that paralyzes homeowners with anxiety: "How much do I ask for my house?"

The process is especially vital for people not using a real estate agent. There are two excellent Web sites that can help. Both let youlook up sales prices of nearby homes. Home Gain's service (at homegain.com) lists each home's address, price, sales date, number of bedrooms, square footage and approximate year built.

A competitor, Home Price Check (homepricecheck.com), offers a shorter list, giving each home's address, month sold and the number of bedrooms and bathrooms.

"It's a great way to understand the value of real estate because it's the raw data," says Ben Joslin, general manager of Domania, the unit of Lending Tree that operates Home Price Check.

Agents also estimate home values by finding comparable houses (called "comps").

Colby Sambrotto, chief operating officer of ForSaleByOwner.com, sends his clients to Home Price Check. It beats going to the county recorder's office to look up real estate records.

Bob Moulton, president of Americana Mortgage Group, advises buyers to go online and check recent sales, especially when the seller isn't using an agent.

In coming up with an opinion on a home's market value, the gold standard is to hire a licensed appraiser, the best source of unbiased opinion. A full appraisal -- called a complete summary appraisal -- requires interior and exterior inspections, photos, drawings and comparisons with at least three nearby homes sold recently. It can cost several hundred dollars and requires the owner's cooperation, which you might not get.

To save money, you could ask an appraiser to prepare a condensed analysis, called a 2055 form, with or without an interior inspection.

For even less, you could get an automated valuation model, or AVM, a computer estimate of the home's value.

Many real estate-oriented Web sites have links to AVM services. Domania offers an AVM service called Value Check. Other sites offering AVMs include Home Gain and Electronic Appraiser (electronicappraiser.com).