PHILADELPHIA  Shawn Hebb may have one of America’s toughest jobs: convincing people that Whole Foods Market can be an economical place to shop.

This week, leading five customers through a store here, he breezed past the triple cream goat cheese, $39.99 a pound, and the fresh tuna, $19.99 a pound, to focus on the merits of beans, chicken thighs and frozen fish.

Then he held up a $1.50 package of tofu. “It looks gross but it’s delicious,” he said.

Whole Foods Market is on a mission to revise its gold-plated image as consumers pull back on discretionary spending in a troubled economy. The company was once a Wall Street darling, but its sales growth was cooling even before the economy turned. Since peaking at the beginning of 2006, its stock has dropped more than 70 percent.

Now, in a sign of the times, the company is offering deeper discounts, adding lower-priced store brands and emphasizing value in its advertising. It is even inviting customers to show up for budget-focused store tours like those led by Mr. Hebb, a Whole Foods employee.