(MONEY Magazine) – Your mom isn't the only person who clips supermarket coupons. According to a recent survey by Visa, 72% of Americans who earn more than $125,000 use them, compared with 65% of the population at large.

Problem is, it's not such a great idea. Research suggests that coupons actually cost shoppers money. Tests of a new supermarket scanning gizmo in Syracuse, N.Y. last fall showed that people who used coupons spent 8% more than folks who didn't. This follows a 2002 study co-sponsored by Washington University in St. Louis that found that shoppers spent an extra $8 on unplanned and luxury items for every $1 coupon they used. "Steak, flowers, candy--people were treating themselves because they felt so good after using coupons, and of course they spent a lot more on the treats than they saved on the coupons," says marketing professor Ambar Rao, one of the 2002 study's authors. Coupons can save you money on some things you buy a lot (see below), but proceed with caution. --ETELKA LEHOCZKY