How long can Walmart remain the low-price leader?

With the changing economy, mega-retailer Walmart faces a price competition from higher -- and lower-priced stores A Walmart store. (ROBYN BECK/AFP/) JEREMY HOBSON: We'll get quarterly earning reports this morning from Target and Abercrombie and Fitch -- and maybe they'll say something that'll lighten the mood in the retail sector after Walmart said yesterday that its US sales were down for the 9th straight quarter. So what's the matter with the world's largest retailer? Here's Marketplace's Eve Troeh. Eve Troeh: Walmart has always sold itself as a low-price leader. And customers bought that, until the last few