I got my start in my late teens. My mother had a consignment shop/bridal store, which every so often garnered the odd donation of designer clothes. Since this wasn't exactly the kind of place someone came to buy Tommy Hilfiger jeans or a Ralph Lauren sweater, my mother gave me the pick of the donations. Once in a while, I'd find something that fit me, but most of the time, I was hunting for returnables, clothes I could pass off as having been bought somewhere else.
In those days, J.C. Penney had the loosest return policy. No receipt? No tags? No problem. They gave the item a once-over and found something comparable in quality to gauge the price. Most stores issued a gift card to a customer without any real evidence of purchase; J.C. Penney always gave cash.
This was in the mid-1990s, before you had to show ID, sign a slip of paper and answer a battery of questions from the always skeptical supervisor. It was just you, the cashier -- and a question of control. You always had to know who was going to be behind that register. That was the golden rule: know your mark. Know whom you could work over and whom you couldn't.
This was something I learned from watching my mother, who knew all too well how to root out a good con. Her defining scam was the Christmas special, when, on the day after Christmas, she'd gather up the presents from under the tree and return them to the stores along with the masses -- poor Mommy forced to return all of her thoughtful gifts. But unlike most of those people, she'd circle back to the stores (once the shift change had taken effect) and repurchase those same presents for vastly reduced prices. Was this out of necessity? Was it out of some need to display her cunning? Looking back, I suspect my mother had become convinced of some higher moral agenda, in which the weak (the middle class) outfox the strong (the rich). All I know is that we always got what we wanted for Christmas.
My mom sold the consignment shop when I was in my 20s. By then, I'd decided to become a writer, having fallen in love with "The Catcher in the Rye" at the age of 17. A college student lacking the funds to feed my literary appetite (and with a habit of underlining passages that eliminated the public library as an option), I stopped returning clothes -- and started returning books.
http://www.salon.com/life/feature/2010/11/29/life_as_an_amateur_con/index.html