Consumer Reports asked experts as well as our Facebook followers for their best time- and money-saving food shopping tips. Pick a few of these tactics to try in the coming weeks; you could shave up to 40 percent off your bill.

1. Look high and low. You’ll find the lower-cost ­generic versions of ­cereal, cake mixes, paper goods, and other high-turnover staples on the very lowest and highest supermarket shelves. Retailers can charge manufacturers a fee to be at eye level.

2. Use discount apps. Two we like are Ibotta and Flipp. Both coordinate your store loyalty cards with current discounts and coupons. With Flipp, you scan the app with the market’s checkout scanner to apply savings at the point of sale. With Ibotta, you select rebates in the app and photograph your receipts to import savings to an Ibotta ­account. Savings are transferred to a payment app, such as PayPal, or a gift card. “I recently cashed out for $100 in Amazon gift cards,” says Geriann McMurray-Markwell, an Ibotta user in Nampa, Idaho. “It took me about a year but was totally worth the minimal effort.” Mary-Ann Johnson of Flagstaff, Ariz., says she uses Kroger’s club card app to get free products and samples. Some loyalty programs, notably Safeway and Stop & Shop’s, also let you build rewards toward gas purchases at affiliated gas stations.

3. Get navigation help. Some store loyalty club apps let you locate items by aisle, which can help you avoid crisscrossing aisles—and avoid more temptations. At major chains, the Flipp app can do the same.

4. Keep a calculator handy. Unit price shelf stickers under each product can help you compare. But if the store doesn’t have the stickers—only nine states require them—use your smartphone’s calculator. Divide the price by the number of units in each package you’re comparing. If, say, one soda’s price is per fluid ounce and the other’s is per liter, ask Google how many ounces are in a liter and do the conversions. Consumers Union, the policy and mobilization arm of Consumer ­Reports, urges super­markets to put unit-pricing stickers on their shelves.

5. Ask for a rain check. When a sale item is sold out, ask a store employee for a rain check—a ­paper IOU—that you can use like a coupon when the item is in stock. “I’ve saved hundreds of dollars this way,” says Jeanette Pavini, a consumer savings analyst at Quotient, which is based in Mountain View, Calif., and runs the shopping app and website Coupons.com.

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6. Go with store brands. CR’s trained tasters have found store brands with quality equal—or supe­rior—to that of brand-name items, at prices usually 15 to 30 percent lower. That’s because generics are sometimes made by the same companies that make the big-brand foods. Trader Joe’s was a standout for its store brands in our survey. In past taste tests of 57 store brands, we found that 33 were as good as or better than the comparable name brand, including those in the product categories of frozen shrimp, roasted cashews, cranberry juice cocktail, ketchup, maple syrup, mayonnaise, frozen mixed vegetables, shredded mozzarella, and ­vanilla ice cream.

7. Use a cash-back card. We found great potential savings from the American Express Blue Cash Preferred card, which pays back 6 percent on the first $6,000 in groceries each year, as well as 3 percent on gas and department-store purchases, and 1 percent on other purchases. It also returns $150 if you spend $1,000 in the first three months. A user spending $200 monthly on gas, $500 on groceries, $100 on department-store buys, and $300 on other items would save $583 in the first year of card owner­ship and $1,449 in the first three years, even factoring in the $95 ­annual fee. 

8. Shop at quiet times. Accord­ing to a survey by the Time Use Institute, a consulting company, the busiest food shopping time on weekdays is from 4 p.m. to 5 p.m. and the least busy is before 8 a.m. and after 6 p.m. On weekends the peak shopping time is from 11 a.m. to noon.

9. Inspect store circulars. Only 46 percent of millennial shoppers in our recent survey said they read store circulars for weekly sales, compared with 51 percent of Generation Xers and 63 percent of baby boomers. Most circulars are online, making the task of checking them pretty painless even for the digital-first crowd.

10. Embrace coupons. Find stores that double or even triple manufacturers’ paper coupons. Certain retailers do it every day or week, others less regularly. In the Northeast, Stop & Shop doubles manufacturers’ paper coupons every day. Bi-Lo, in Georgia, North Carolina, and South Carolina, doubles coupons with a value of 60 cents or less every day, unless noted otherwise at the individual store. (With both chains, other restrictions apply.)

11. Do a pantry inventory. Americans throw away about a quarter of the food and beverages they buy, at a cost of up to $2,275 ­annually for the average family of four, says the Natural Resources ­Defense Council. Use the free USDA FoodKeeper app for guidelines on how to store foods. Or do as Maggie Pallan, a professional chef in Las ­Vegas, does. She maintains a spreadsheet of what she has at home, to avoid buying duplicates. “I treat my home grocery shopping the same as my business,” she says.

12. Get senior discounts. Several chains, including Bi-Lo, Harris Teeter, Hy-Vee, and Publix, offer 5 percent discounts, either on specific days or when you present a special store ID card. The Fred Meyer discount is 10 percent. In some cases you must be at least 60 to qualify.

13. Weigh bagged produce. Prebagged produce is usually cheaper by the pound than individual pieces. Use the produce scale to compare bags because they’re not uniform in weight. A CR reporter found 3-pound bags of red delicious apples at a Stop & Shop near our Yonkers headquarters weighing from 3.06 to 3.36 pounds, a 10 percent bonus.

14. Buy in bulk. When 10 cans of your favorite soup go on sale for $10, load up. If you don’t have room to store that many, check the promotion wording to see whether you’re required to buy all 10 for the discount.

15. Track prices. For a few weeks, record prices of the items you buy the most when food shopping. “You’ll be able to find the best prices for specific goods and can stock up when a true price drop happens,” says Terrence Briggs of Germantown, Md. Price-tracking also helps you see when a “10 packages for $10” sale really is a sale and not just a come-on.

16. Find online bargains. Online grocery stores often waive the delivery fee or give discounts for first-time customers. Even with the delivery charge, buying online can help you ­uncover savings for certain kinds of foods, notably snack bars, specialty diet food, coffee, and pasta, says Sam Gagliardi, head of e-commerce at IRI Worldwide, a market research company in Chicago. Online vendors such as AmazonFresh often offer prices up to half off regional grocery chains’ prices because they match Walmart and warehouse clubs’ national prices, Gagliardi explains.

17. Shop the drugstore. Convenience stores, drugstores, and even gas station mini-marts can sometimes beat prices at traditional markets for staples such as milk and eggs. But be mindful of expiration dates, advises Heidi Chapnick, a partner at FreshXperts, a fresh-food retailing consulting company in Mamaroneck, N.Y. Food that has outlived its expiration date can still be sold, assuming it is “wholesome and fit for consumption” and not dangerous to consumers, according to the Food and Drug Administration.

18. Beware of prepared foods. Ready-made items such as cranberry couscous or lemon orzo with pine nuts can tempt when you’re in a rush. But for simple items—say, sautéed greens—home prep can cost about half the price and take less than half an hour of work, our CR food experts say. A home-prep bonus: fewer unnecessary ingredients. A 2016 CR report found that supermarket-­prepared items might not be made in the store and might have preservatives and excess salt.

19. Look for ‘as is’ items. The overripe bananas you’ll find at a discount could be perfect for homemade banana bread. Learn where stores have their clearance sections, says Annette Economides, who with her husband, Steve, runs the website MoneySmartFamily.com. Publix stores, for ­instance, place clearance items on a dedicated rack.

20. Bring your own bags. This might make loading take a little longer but could also save you money at stores that charge for bags, as more and more municipalities require them to do. You’ll also help reduce plastic waste in the environment. Find out how to keep permanent shopping bags germ-free.

21. Shop on weekdays. Certain items are cheaper on weekdays, when stores seek to clear inventory, says Bryan Leach, founder and CEO of the shopping app Ibotta. Consumer data collected through his app show that beer is 9 percent cheaper on Monday and most costly on Saturday, he says. Other best days to buy: Monday for ice cream and beauty products, Tuesday for wine, Wednesday for produce (though it’s only a 3 percent discount), Thursday for cleaning products, and Friday for snacks. Monday, he adds, is the most pricey day for produce.

22. Use your freezer right. Freezing large quantities of sale and seasonal food saves the average family of four $2,000 per year, Annette Economides maintains. “Why pay $4 a pound for blueberries in winter when you can thaw the ones you bought in summer for 99 cents?” she asks. The Economideses even freeze milk and cheese. Every 30 to 60 days they check the freezer and build menus based on what’s there.

Editor's Note: This article also appeared in the July 2017 issue of Consumer Reports magazine.