(MONEY Magazine) – Every day, women pay more than men do for virtually identical goods and services. You may already have heard that dry cleaners sometimes charge women as much as three times more than men pay to launder the same type of shirt. But what you probably don't know is the range of items and services for which women pay more. Even women's deodorants are commonly priced 50% higher per ounce than the same formula marketed to men. Women need to be aware of the discrepancies--and fight back.

Throwing a spotlight on the issue has worked in California and Massachusetts. A California woman who pays more than a man for any comparable item can now go to court and win up to $1,000 plus her attorney's fee. Massachusetts regulators have helped reduce inequitable pricing at cleaners, hair salons and department stores.

But there's probably no such law where you live. That's why you'll want to know about these ways women commonly pay more than men do and what they can do about it:

--Automobiles. Even though women account for nearly half of all U.S. car sales, a 1990 study found car dealers routinely charge women more than male buyers. In a report published in the Harvard Law Review, researchers posing as car buyers made 165 visits to Chicago-area car dealers. The result: Car dealers made as much as 37% more profit off women buyers.

Car salesmen, of course, are looking to make the maximum profit they can. That's why, no matter your gender, you'll get taken more seriously--and probably pay less--if the salesman realizes you're familiar with the car and have a firm price in mind. So check the sticker price and the estimated dealer's cost [published in MONEY's March issue]. Ashly Knapp, president of AutoAdvisor Inc., a consumer consulting group, suggests starting negotiations at about $300 above the dealer's cost. If the best offer you hear seems high, say that you plan to check out other dealers. A smart salesman will come down in price.

--Clothing. Frequently, similar garments cost more if they're found in the women's department. Need proof? In 1994, the Washington Post compared two wool DKNY turtleneck sweaters and found that they were nearly identical with one difference: The men's sweater cost $97.50; the woman's was $145.

When shopping for unisex clothing like polo shirts or running shorts, women can save by stepping across the aisle to the men's section. For items like dresses and suits, shop around for the best price. And if you know you can get something cheaper elsewhere, ask the store clerk for a price reduction. You just may get it. Merchants won't change their dual pricing practices until women make their outrage known to retailers and clothing manufacturers.

--Health care. Even when women report the same type of illness or medical complaints as men, females undergo more examinations and lab tests, are given more prescriptions and are told to come back for more repeat visits, according to a 1991 American Medical Association report. Women often say the problem is a communication gap with male doctors.

So consider choosing a female physician. Even when you find a doctor you trust, always inquire about the need for a diagnosis or medication to be sure you're not overpaying. You pay the bills, so you have the right to expect quality and a reasonable price.

THIS MONTH'S EXPERT Frances Cerra Whittelsey is co-author of Women Pay More and How to Put a Stop to It (New Press, $9.95) and works in New York City. She has also developed a site on the World Wide Web (http://www.sis.org) that provides information on women's consumer issues and explains what to do if you think you've been overcharged. She spoke recently to Money senior reporter Amanda Walmac.