10 Worst Things to Buy in Bulk at Costco

1. Fresh produce

Fresh fruits and vegetables are certainly healthy, but they have a short shelf life. Unless you have a large family to feed, you probably won't be able to get through that 10-pound bag of onions before they start to go bad.

Think about it, can you get through a prepackaged bunch of bananas – at Costco you can’t break them off into smaller bunches like you can at a supermarket – before they turn brown and mushy? How about a 5-pound bag of apples or an enormous container of mixed lettuce?

“If you serve a salad every night with dinner, get the giant bag of mixed greens. If not, get your greens at the grocery store,” shopping expert Trae Bodge shares.

2. Frozen produce

Unlike fresh produce, frozen fruits and vegetables can’t go bad. Or can they? Shopping experts advise consumers to stay away from the freezer case. That big bag of frozen broccoli that seems like such a bargain might not be in the end.

“Oversized bags of produce may seem like a great idea, but every time you open the bag, the frozen food is exposed to fresh air and can cause freezer burn,” says money-saving expert Andrea Woroch. “I find it’s better to buy smaller bags of frozen vegetables and fruit from a local grocery store and look for deals on the store brand to save.”

Vegetables can be stored for up to 3-6 months in the freezer before the quality starts to get compromised, according to Good Housekeeping. So unless you're a veggie fanatic, you might be better off buying smaller bags of frozen vegetables and leaving behind that giant box of peas.

If you insist on buying the Costco-sized bags of frozen veggies, at least portion them out into smaller bags when you get home. That way, most of it can stay at a consistently cold temp while only the veggies you're using that week get exposed to fluctuating temperatures. 

3. Liquid cleaning products

It might come as a surprise, but liquid cleaning products don’t last forever. As such, buying them in bulk isn’t necessarily such a thrifty idea.

“Liquid cleaning products tend to become less effective over time, so they are best to buy in smaller containers unless you regularly do laundry for a big group,” says Bodge. Anything containing bleach, for example, only has a shelf life of six months. If you've got a bottle older than that, you're not getting the same sanitizing or stain removing power as you got when it was fresh. While other ingredients in liquid cleaning formulas typically last about one or two years, their potency still degrades over time, as do any fragrances you might have chosen the product for.  

Bodge instead recommends powdered cleaning products, as they have ”an unlimited shelf life.” Of note, Consumer Reports gave high marks to Costco’s Kirkland Signature powdered detergent. The product-testing outfit lauded the store-branded detergent’s stain-fighting abilities and low cost per load.

4. Cereal

You run the risk of your cereal going stale if you buy it in bulk and don’t eat it fast enough. But shopping experts say there’s an even bigger reason to avoid the cereal aisle at Costco: You can get a better price on a box of name-brand cereal at the supermarket by combining sales and coupons.

“If you watch your local grocery store and find a sale, you can pair that with a coupon and get a much better price than you would getting that big box at Costco,” says Fobes. Costco doesn’t accept manufacturer coupons, she notes.

Bodge echoes Fobes’s advice, “For cereal, soda, canned goods, eggs and milk, it would be wise to compare the unit prices between the price club and your grocery store,“ she shares. Buying in bulk isn't always the cheapest option, sometimes you might get a better deal by using a grocery coupon.

5. Over-the-counter medicines

Costco’s pharmacy aisles (next to the pharmacy, naturally) are chock full of those extra-large bottles or boxes of over-the-counter medicines, from sinus medication and aspirin to vitamins and diet supplements. You’ll do better shopping elsewhere, saving experts say, as it's unlikely you'll be able to get through one of these bottles before it expires. 

“Since over-the-counter medicine is taken on an as-needed basis and has expiration dates, an oversized bottle of ibuprofen will likely never get used up before it goes bad,” says Woroch. “You’re better off buying it when needed from your local drugstore or big-box retailer and opt for the generic to save 30%.” 

Woroch recommends using the Flipp app to compare store circulars to see which retailers are offering the biggest discounts on the OTC meds you need when you need them.

6. Personal care and beauty products

Be cautious when weighing whether to buy personal care or beauty products in bulk at Costco, advise the shopping experts we talked to.

“Only buy items that you go through quickly — for example, body lotion, shower gel and hair conditioner. If there’s something you use only sparingly, like an eye cream, face cream or antiseptic ointment, I would not advise buying it in bulk,” says Bodge. “Sunscreen products also have a limited shelf life, so if the whole family is using it, great. If it’s just you, get it at the drugstore.”

Tracie Fobes agrees: “Drugstore deals on personal care products can often be a much better deal than the big bottles you buy at Costco.” Combining sales with coupons will yield the best prices. (Again, Costco won’t take your coupons).

7. Canned vegetables

A 12-pack of canned creamed corn may look like a great deal at Costco, but look closer and you’ll notice those cans have expiration dates on them. And really, how much creamed corn can you go through in a year?

If you prefer national brands, hold on to your manufacturer coupons until your brand of choice goes on sale at the supermarket. Grocers hold frequent sales on canned goods. Don’t be surprised to see “buy-2-get-3-free” deals periodically. Shopping experts say February is a particularly good month for big sales on canned goods.

Alternatively, sample the supermarket’s generic brand. The everyday price per can might even be lower than the per-can price of a national brand purchased in bulk at Costco. “You can find better deals on generic brands at the grocery store,” says Woroch.

8. Salty snacks

As with bulk-purchase cereal, you run the risk of your salty snacks going stale if you buy them in oversized packages.

“Chips, cheese puffs and other snacks are probably cheaper in bulk, but it’s not a good deal if half the bag goes stale,” says Bodge. “There are only three of us at home, so I only buy snacks in bulk if we’re planning to have company.”

Smaller bags of name-brand potato chips, tortilla chips and similar salty snacks frequently go on sale at supermarkets, sometimes at 50% off. Stock up ahead of major sporting events, when snack manufacturers run some of their best promotions.

9. Spices

For home cooks, buying spices in bulk usually doesn’t pay off. This is especially true when it comes to those spices that you rarely use in your go-to recipes. Good luck ever getting to the bottom of that two-pound container of fenugreek.

Worse, spices lose flavor and potency over time, especially if its ground. The longer you keep a spice in the pantry, the less flavorful it becomes. According to Bon Appétit, you technically shouldn’t keep ground spices for more than three months and whole spices should only be stored for up to eight to 10 months.

10. Cooking Oil

Unless you’re running a restaurant or deep-frying turkeys on weekends, those bulk sizes of cooking oil aren’t the bargain you think they are.

That’s because cooking oils, like other products on this list, have a relatively short shelf life. Olive or vegetable oils can be kept unopened in the pantry for four months, according to the USDA. This is especially important for any oils you might eat fresh, like that extra virgin olive oil you drizzle over your salad. The rancid flavor of expired olive oil can ruin your favorite salad dressing recipe. 

Any money you might’ve saved up front is lost once you’re forced to dump out rancid oil. So no, you probably don't need to buy that three-liter bottle of Kirkland Signature olive oil for $36.99.

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