When you make a grocery purchase using a shopper’s card, your receipt usually proclaims you have saved x amount of money. But did you really save money? Maybe not.

A new study by the Wall Street Journal found no noticeable savings using these cards. In fact, the study determined that you were far more likely to find lower prices at supermarkets that don’t use cards.

The study compared stores that offered loyalty cards with those that did not in five cities around the country. In each city, a “super center” or warehouse store sold the same groceries for less, without the purchaser having to use a card. In their defense, stores that use cards say it is unfair to compare them with warehouse stores that may offer less selection.

Surely these findings will be hailed by consumers who refuse to use these shopper’s cards because of their concerns about the privacy implications of collecting information on their shopping patterns.