Ann Natunewicz, manager of retail research at Colliers International in Washington, DC, says that "as far as regional concentration goes, there are relatively fewer dollar stores in the Northeast than there are in other parts of the country." In the Northeast, drug store chains rule the value sector. But Natunewicz adds that the dollar store chains are looking at every market nationwide.

"Some, like Family Dollar, have absolutely no problem going in and shoving themselves right in next to retailers they believe they can compete with," she says. "It's because they believe that they have a better offering and a better value proposition for the consumer."

Natunewicz and colleagues at Colliers International wrote a January white paper on dollar stores that looked at the nationwide expansion programs of the four major chains, which includes 99¢ Only Stores in the mix. The paper found these four chains currently operate 21,500 locations in the US and occupy an average of 7,000 to 10,000 feet. This smaller footprint gives them a leg up in many markets where the larger real estate requirements of big box retailers keep them out of smaller markets.

The strongest point for dollar stores, though, is that most experts agree that their appeal will linger, even as the economy improves. "Approximately 20% of the households that earn over $100,000 admit to shopping at dollar stores," Jaggi says, citing a Chase Bank study.