Not long ago stickers were pretty much restricted to the cheerful Chiquitas that clung to bananas. These days the under-12 set is snapping up virtually anything in sticker form and affixing it to notebooks, lockers, tennis shoes, T-shirts, socks and assorted body parts. Stickerphiles can now choose among a vast array of whimsical designs, including 3-D Mr. Ts and scratch 'n' sniff Barbies (which reportedly smell "virginal").

The collectors, most of them prepubescent, flock to sticker conventions, where they swap choice "puffies" (foam-filled, vinyl-coated models), "googlies" (stickers with roll-around eyes) and "liquid crystals" (stickers filled with a chemical that causes them to change color when rubbed). The kids labor over sticker scrapbooks, band together in sticker clubs and subscribe to journals like Stickers! magazine. Last year they invested in more than a billion stick-ons priced at five cents to $5, spending as much as $500 million, according to one estimate. "Stickers are the hottest thing in our store," says Bill Zwecker, owner of a large Chicago gift shop called Animal Accents. "They're this generation's baseball cards." Stick-on bears are practically lumbering out of the store. "We absolutely can't keep them in stock," Zwecker reports.

Like most pop-culture epidemics, stickermania was spawned in California. Four years ago a customer at Mrs. Grossman's Paper Company in San Rafael, Calif. asked proprietor Andrea Grossman for a heart-shaped sticker to decorate her envelopes. Grossman, now 50, made a flock of hearts, sold them on a roll and attracted so many adherents that she now peddles 150 varieties worldwide.

Although most sticker fanatics are young girls, Mary Liz Curtin, Mrs. Grossman's sales director, reports that grown-ups, too, are getting stuck on stickers. Party givers bedeck their invitations with them, dentists use them to reward juvenile patients for bravery, and teachers—who once had only the traditional gold star at their disposal—bestow them on their best students. It's a bona fide sticker stampede, and no wonder, says Curtin: "Where else can you have so much fun for a dime?"