No, the price tag on that $9 jar of mayonnaise isn’t an upside down 6.

Grocery costs have risen 25% in the past three years. To save money, shoppers are increasingly turning to no-frills retailers focused on cheaper, private-label brands or bulk quantities, such as Aldi, dollar stores and Costco.

They’re also discovering the so-called “thrift stores” of the grocery world, such as Minnesota’s Mike’s Discount Foods, which sell items that regular supermarkets reject — including mainstream consumer brands and organics — at steep discounts. The family run business gleans items that are approaching or have passed their best-if-used-by date, seasonal goods in dated packaging, overstocks, closeouts and even food rescued from truck accidents.

Mike Abernathy, who founded the business in 1989, originally picked up items from local supermarkets in his van. But now that the company has grown to six locations, several of which are in the north metro, it works with grocery distribution centers nationwide.

Legally, Mike’s is a salvage grocer, but the company prefers the term “discount,” said Tony Oelmann, Mike’s longtime general manager. “When you hear salvage, you think junk, and it’s not.”

For example, staff at a regular supermarket might check an arriving semi-load of strawberries, find a few moldy ones, and reject the whole lot, Oelmann explained. But that doesn’t mean the load doesn’t have value. Mike’s staff will buy it at a modest price, cull the bad berries and pass along the savings.

The Fridley location is among the largest Mike’s stores (the others are in Anoka, Braham, Comfrey, Hilltop and Princeton), with a wide selection of produce, meat, dairy and packaged goods. On a recent visit, the only staple noticeably absent was milk.

Several odd, limited-edition or seasonal flavors caught my eye right away: 7-layer-dip Kettle chips (2/$5), frosted lemon Cheerios (2/$5) and Yelloh! (formerly Schwan’s) pumpkin cheesecake ice cream ($5 for 1.5 quarts).

After spotting big bags of apple-pie-flavored Pearson’s salted nut rolls (2/$10), I also noticed several other local brands, including Ellsworth cheese curds (2 bags/$10) and Olsen herring cutlets ($10 for a 2-pound party pail).

I didn’t expect to see premium items in the bare-bones warehouse, but Mike’s had European-style butter (3 oz. for $2), Organic Valley eggs ($2 a dozen), organic broccoli (a buck a stalk) and Whole Foods’ store brand organic carrots ($1.49 a bag).

Best-by dates were imminent for most perishables, but the U.S.D.A. and food-safety experts note that those dates are about quality, not spoiling. The $2 boxes of Honey-Maid graham crackers were a month past their best-by date, but fresher than last summer s’more-making leftovers in my own cupboard.

The only produce I saw at Mike’s that looked past its prime were some $1, 1-pound cartons of strawberries that contained a few brown or mushy berries. The raspberries, blueberries, mini-cucumbers and mandarins I bought at half their usual price looked and tasted fine. So did everything else I purchased. (Mike’s offers exchanges to unsatisfied customers. It’s also worth noting that everything is 10% off on Tuesdays.)

Just past the meat aisle (ham for $3/pound, brisket for $5/pound), I was surprised to find huge bins of clothing marked with Target clearance tags for $3 an item. This was a new venture, Oelmann said, but last winter’s fuzzy sweaters and sequined holiday wear were selling well enough that it likely will continue.

Mike’s business has been growing every year, Oelmann said, and confirmed that moneyed folks shop there, too, based on the occasional Tesla or Mercedes in the parking lot.

“They’re smart with their money, and they figured out there’s nothing wrong with the stuff here,” he said.

Other ways to save on groceries

• Most traditional supermarkets maintain a small display of goods they’re trying to unload, such as holiday-themed baking mixes or brands they’re no longer carrying, that’s worth checking out.

• So Low Grocery Outlet in north Minneapolis offers a lot of liquidated items alongside traditional supermarket amenities, such as a meat counter.

• Lesser-known spots to buy bulk groceries include Costco Business Center in Minneapolis, Restaurant Depot (the Brooklyn Center location is open to the public), and Sysco’s retail store in St. Cloud.