WF (or Trader Joes for that matter) simply doesn't sell value priced versions of a lot of items. CVS will sell it at a ripoff. It probably comes out close to a wash put poor people are poor, not stupid. If the numbers worked out in favor of WF they would be shopping there. Also, nobody(TM) does their entire shopping at CVS. People will drag their asses elsewhere on a regular basis to buy certain items that are cheap. Many convenience stores, bodegas, etc. will sell a couple staples or classes of items dirt cheap in order to attract business. You buy your regular items where they are cheap (e.g. $1.50/gal brand name milk from the bodega that buys about to expire milk from a restaurant supplier for pennies and passes on the savings to create foot traffic) and buy everything else at CVS.