It's not exactly a free lunch, but close.

Supervalu told customers Wednesday that it would give them $20 or $30 of free groceries, provided they buy a $250 or $300 grocery gift card. Its so-called "refund rewards" program starts Sunday.

The program comes amid tough times for traditional grocers such as Supervalu, which have lost market share to Wal-Mart and Costco as consumers trade down during the toughest economy in decades.

"We know that consumers' budgets are strained like never before, so we're looking for ways to help our shoppers find value at the grocery store," said Jeff Noddle, Supervalu chairman and CEO. Even he has been bemoaning the high cost of groceries, trying to pressure national-brand food suppliers -- the Krafts, General Mills and Unilevers of the world -- to lower prices.

The refund program ends April 15. It's valid at Supervalu's retail stores, including Cub Foods, Acme, Albertsons, bigg's, Farm Fresh, Hornbacher's, Jewel-Osco and Shaw's/Star Market.

The program is similar to one Supervalu ran last year, as stimulus checks were distributed, in which the company added $30 free to every $300 gift card purchased with a stimulus check.

Spokeswoman Haley Meyer wouldn't give details of how many shoppers cashed in on that deal, but said the company was "pleased with the success of the program."

Matt McKinney • 612-673-7329