Each economic era has its catchphrase. The 1990s bull market was the age of "irrational exuberance." The Great Depression left us with "Hey brother, can you spare a dime?" Today's world of soaring supermarket prices gives us the term "salvage groceries."

Skyrocketing prices for eggs, milk and bread have sent waves of new customers to places like the So Low grocery outlet in north Minneapolis and Mike's Discount Foods in Fridley. Operating at the fringes of the food industry, the stores are among a handful of super discount "salvage" grocery stores hawking packaged goods, produce and fresh meat at prices that recall another time: milk at 99 cents a gallon, bananas 25 cents a pound, packets of oatmeal, 10 cents.

Of course there's a catch. Much of the food is expired or about to expire. It's culled from the aisles of mainstream supermarkets where managers are eager to move products out of the way before new shipments arrive. Some of the food comes from expired marketing campaigns. And some of it comes from boxes damaged en route to other grocery stores, even from truck turnovers.

"You'll never know what you'll find here," said Darren Godes, co-owner of the So Low Grocery outlet. Sales have climbed at the family-owned store by about 30 percent in the past year, he said.

Godes, who with his brother inherited the store from his father, said he feels rotten when he has to raise prices.

"We struggle on the milk and eggs because it's going up along with everyone else," he said. Still, on the day he said this, he had a special for soon-to-go-bad milk selling at 99 cents a gallon.

"I always check the dates," said shopper Bertha McKinney, who was shopping at the So Low Grocery outlet last week. The meat counter brings her back, because it allows customers to buy as much chicken as they can afford, packaging the pieces after the customer chooses them from a glass case.

McKinney, who also runs an in-home day care, said if it weren't for places like So Low Grocery she couldn't afford to feed the eight people she cooks for.

The stores rely on customers to check the products and will replace anything that's questionable, but expiration dates on packaged goods are more elastic than most customers realize, said Mike Abernathy, the owner of Mike's Discount Foods, where monthly sales are up 25 to 30 percent compared with a year ago.

"It's basically a guideline. It doesn't mean that a lot of this stuff is shot," he said.