Wal-Mart Stores, Inc. (NYSE: WMT) made global headlines over a year ago when the world's largest retailer announced plans to have a whole slew of $4 generic drug prescriptions available at its U.S. locations. Other retailers followed (not all), and Wal-Mart's hope was probably that $4 generic prescriptions would lead more customers into stores.

The retailer reported that it has "saved" customers nationwide more than $1 billion, with the top "savings" states being Texas at $132.6 million; Florida at $72.4 million; North Carolina at $48.2 million; and Georgia at $42.3 million. Wal-Mart also reported that almost 30% of those prescriptions are filled by customers without insurance.

But my question is this: how is Wal-Mart measuring this amount? Sure, one can say that the difference between an average generic prescription drug price and the newer $4 rate equals this amount -- and call it a "savings." That's probably the way this is being measured, and I don't see a problem with that. In addition to that, Wal-Mart forced the hand of competitors to lower these generic prescription prices as well. Will Wal-Mart use more than a press release to let customers know about this? Let's hope so -- because it lets too many good PR opportunities slip by without due promotion. This one is a biggie.