
Buy: Prescription Drugs
When Consumer Reports called more than 200 pharmacies nationwide for prices on a month’s supply of commonly prescribed drugs, it found a 450 percent difference in cost between the highest- and lowest-priced stores. Drugs at big-box store pharmacies were much cheaper than those at many drugstore chains, especially if you opt for generics. Plus, you don’t need a membership—warehouse pharmacies are required by law to remain open to the public. Don’t miss these Costco shopping tips that will save you tons of money.

Buy: Cereal
Stock up on the big-box store version that comes in two large bags to a pack. You can save 60 percent on favorites such as Froot Loops and Honey Nut Cheerios by buying in bulk. Even organic cereals can cost 25 percent less at warehouse clubs. Check out these bizarre things you never knew you could get at Costco.

Buy: Pet Supplies
Certain brands of dog food can be up to 60 percent less expensive at a big-box store compared with popular pet stores, so it pays to comparison shop for your pooch’s favorite kibble. Here are the things you should only buy at Trader Joes.

Buy: Liquor
Some warehouse clubs have partnerships with vineyards that award them deeply discounted prices for bulk purchases—which means you can save about 30 percent on certain wines. Warehouse store brands of other liquors, like Kirkland vodka, can cost nearly 40 percent less than premium brands like Grey Goose. Depending on your state laws, you may not need a membership to purchase liquor at a club store. Since you’re a fan of shopping at big-box stores, you won’t want to miss the secret code behind Costco’s prices.

Buy: Men’s Dress Shirts
Clothing is often deeply discounted but still of good quality at a big-box store. We’ve seen men’s dress shirts at a warehouse store for 30 percent less than popular retailers.

Buy: Charcoal
Though it comes in large quantities—typically two 20-pound bags packaged together rather than a single five- to ten- pound bag—charcoal is usually less expensive at the big-box store than at supermarkets. During grilling season, you’re likely to use it up quickly. Even if you don’t, charcoal has an indefinite shelf life if stored in a cool, dry place. Here are some Costco shopping perks everyone should know about.

Skip: Over-The-Counter-Medicine
You probably don’t use OTC medications every day, so that jumbo bottle of pain reliever from the big-box store might expire before you can finish it. Choose a regular-size bottle of a generic brand at your local drugstore or supermarket. Don’t miss these other things you should never buy at Costco.

Skip: Cleaning Supplies
Liquid cleaners typically lose some effectiveness after six months to a year (certain powders may have an indefinite shelf life if stored in a cool, dry place). Unless you have a large family, purchase household supplies like window cleaner, dish detergent, laundry soap, and bleach in regular-size containers at retail stores.

Skip: Paper Goods
Common household items go on sale so often that supermarket discounts may be deeper than big-box store price cuts. Pairing store sales with manufacturer coupons can dramatically shrink your bill.

Skip: Meat
Supermarkets rotate sales on various meats so shoppers will come for cheap prices and then buy more profitable packaged goods. Manager markdowns are also often available when meat nears its expiration date. Next, check out the secrets Costco employees aren’t telling you.
Sources: Andrea Woroch, a consumer savings expert; Jeanette Pavini, a savings expert at coupons.com; Trae Bodge, senior lifestyle editor for the Real Deal blog at retailmenot.com; consumerreports.org; kiplinger.com; goodhousekeeping.com; today.com; womansday.com; thecouponproject.com; and thedailymeal.com