When buying expensive brand-name products or antiques, I urge you to verify the item's authenticity before making an offer. You cannot take it for granted. In 2004, Tiffany & Co. sued eBay, claiming that when the luxury jeweler purchased items advertised as Tiffany on the auction site, nearly three-quarters of the 186 products were fake. eBay didn't deny Tiffany's claims, but argued that because it doesn't take possession of any goods sold on its site, it isn't responsible for authenticating them. (One piece of good news: If the site receives a valid complaint, it will take punitive action on the rogue seller's account.) Caveat emptor is the lesson here. If you've had your eye on a designer sofa that retails for $6,000 and you find it online for half that amount, contact the vendor and politely ask for proof of authenticity, such as copies of written appraisals or additional photos that show distinguishing labels or stamps. If you're not sure what a telltale mark is on a particular item, head to the library for reference books. A lot of this information is on the Web, too.
Another verification option: Get help from a reputable antiques dealer, auction house, or appraiser. To find one, ask your home-insurance agent. You also can try the Web site for the PBS series Antiques Roadshow, which includes a contact list for the experts featured on the program. For any of these services, be prepared to pay a fee—well worth it if the item in question costs a few grand.