Hermès’s Birkin bag is more than an exclusive, elusive accessory—it’s a pop-culture phenomenon. That’s partly due to the mystery surrounding exactly how to buy one. Is there a waiting list or does one simply have to spend enough on ashtrays and scarves?

We may never know, but the purchasing model is almost as innovative as the handbag itself. No wonder so many other brands are aping it. “It’s happening in cars, high-end watches, and jewelry—and it’s not always official,” says Winston Chesterfield, of Barton, a consultancy that advises luxury brands on trends in consumer behavior. “It stems from a sense of greater exclusivity, tribal identity, and snobbery.”