What's your family heirloom really worth?

You've seen it happen a hundred times on antiquing shows: an ugly family heirloom or hideous garage-sale find turns out to be worth five figures.

Does that mean the singing fish or dancing Santa stashed in your garage might pay for that dream vacation or down payment on a summer cottage? Probably not.

But if you want to find out what some of your valuables really are worth in hard cash, it might be easier than you think.

Depending on the object, you can have an appraiser research and give you a written report documenting the item's true value for a few hundred dollars. Or you could get an informal estimate of an item's value from an appraiser or auction house for considerably less.

Thanks to programs like "Antiques Roadshow," people are more interested in discovering the value of their treasures.

People realize they might have "some things that are valuable lurking in their closets and attics," says Pamela Bensoussan, owner of Bensoussan & Associates, an appraisal and consulting firm in Chula Vista, Calif.

But, like the lottery, not every entry is a winner when it comes to cash value. "So many times an item resembles something you see in a book, or on TV, but it's really quite different," she says.

Brian Witherell, co-owner of Sacramento, Calif.-based Witherell's and participating appraiser for the "Antiques Roadshow," says that in his experience, objects will hold a significant monetary value "less than 1 percent of the time."

But he has seen it happen. One find: an item purchased for $5 at an estate sale that turned out to be a late-1800s, custom-made sterling silver sheriff's badge. Value: $5,000.

It can also go the other way. Roslyn Bakst Goldman remembers one client who was getting appraisals on artwork she'd inherited from her father, a collector. The artists were well-known, and the daughter believed the works could "be very important."

But both pieces were lithographs that were produced in large numbers. In addition, neither was hand-signed. "While they did have value, the value was not great," says Goldman, a fine-art appraiser who is also the first vice president of the Appraisers Association of America Inc.

Where to start
If you want to find out what that knickknack, quilt or art object is really worth, start with the Internet. Enter the name of the item, along with any information you might have, into a search engine like Google.

"You'll be surprised at what you might find," says Bensoussan. But "a little bit of knowledge is dangerous, so you can't base any assumptions on what you might find, but it might give you some interesting information."

If your interest is still piqued, you might want to contact an appraiser. The three largest appraisal trade groups are the American Society of Appraisers, the Appraisers Association of America Inc. and the International Society of Appraisers. Through each you can find a member appraiser in your area.

"I wouldn't go to any appraiser who isn't a member of one of the three," says Bensoussan. And many appraisers will be members of several.

Goldman also advises looking for someone who is credentialed or certified in the particular type of object you are having appraised. "Not everybody does everything," she says.

If you don't know what you've got, use whatever clues are available to take your best guess. If you find out your painting is 19th century American rather than 18th century European, your appraiser can tip you off and refer you to another expert.

If you're insuring or selling the object, you probably want a formal written appraisal.

Look for an appraiser who charges a flat or hourly fee, not a percentage of the object's worth. That way, the appraiser can remain neutral and unbiased. Fees typically run $150 to $400 per hour, but the high end is only for something very rare and special, Goldman says.