9 Things I Won’t Buy at Costco

There are many things I always buy at Costco. But there are also things I never — or no longer — buy there.

Not everything the warehouse club sells is a bulk bargain.

I’m not hating on Costco, though. I’m just using the beloved retailer to underscore the potentially high cost of being loyal to a store and failing to comparison-shop.

I’m not just talking about comparing the price of one brand with another sold at the same store, but also about comparing the prices of one retailer with those of another.

I don’t do this unit-based price research for everything I buy, but I do it for items my household uses routinely. You’d be surprised by what you learn this way.

To illustrate, I’ve examined several types of purchases that I don’t make at Costco. Read on to find out where I do buy these items and why.

1. Cereal

Frosted Flakes, Rice Krispies, Shredded Wheat, Special K — whatever cereal brand your household fancies, you’ll likely find it at Costco for less than it normally costs elsewhere. But that assumes you’re above generic and house brands.

Chains like Walmart and Aldi sell their own versions of a lot of big-name cereals. I’ve done the math on several that my household eats and always found them cheaper than Costco’s options.

Aldi has even better cereal prices than Walmart, in my experience, although I’ve only ever found generic Grape-Nuts at Walmart. (The retailer’s Great Value brand sells them as “Crunchy Nuggets.”)

Wondering what else you might be overlooking at Aldi? Check out “My 10 Favorite Things to Buy at Aldi.”

2. Sandwich bags

I reach for a truly reusable bag as often as possible these days. But my household also still uses typical sandwich bags, so it bothers me to reach for a box at the store and not know that it’s the cheapest option that’ll do the job.

I’ve done the math on several types and sizes of these bags. Walmart’s Great Value brand always wins.

As with cereal, part of the problem with buying plastic baggies at Costco is that my warehouse location only carries one brand, which is a brand name: Ziploc.

Ziploc sandwich bags from my Costco store, for example, cost roughly 10% more than Walmart’s Great Value version the last time I compared prices. And the price difference widens for larger and fancier bags.

3. Manual toothbrushes

To be fair, not buying toothbrushes at Costco isn’t so much about price as it is about selection, and I do buy electric toothbrush heads at Costco because of their price.

I prefer manual toothbrushes that carry the American Dental Association’s Seal of Acceptance, though. I’ve not seen them at my Costco store, so I usually order them online or grab them at Walmart or Target.

4. Trash bags

One of my household’s trash cans requires oversized trash bags — roughly 25- to 30-gallon bags — preferably with drawstrings.

The last time I checked, the cheapest option that fit the bill at Aldi (30-gallon bags by Aldi’s Boulder brand) cost 13% less than the cheapest option at Costco (33-gallon bags by Costco’s Kirkland Signature brand).

For a list of Kirkland Signature products that are worth considering, check out “9 Generic Products You Should Be Buying at Costco.”

5. Shaving gel

Shaving gel, like manual toothbrushes, is something I never buy at Costco due to a combination of selection and price.

My sensitive skin prefers shaving gel or cream with as little fragrance as possible. The most affordable such option I’ve found is the Therapeutic Shave Gel from Target’s Up & Up brand. It lists fragrance as its second-to-last ingredient and costs me $2.69. (By federal law, cosmetics ingredients must be listed in descending order of prominence, meaning listed in an order that reflects how prevalent they are, with the ingredients that constitute the largest percentages of a product listed first.)

6. Shampoo

Suave’s Daily Clarifying Shampoo is about as basic as shampoo gets, but it does the job just fine for me. Not to mention I can buy a 30-ounce bottle for no more than $2 at Walmart.

Good luck matching that price at Costco. Even the chain’s house-brand option, Kirkland Signature Moisture Shampoo, costs several times as much for a 33.8-ounce bottle.

To be fair, though, I do buy conditioner at Costco.

7. Grains

My little household can’t always use up a 12-pound bag of rice or even a 5-pound bag of quinoa before its expiration date passes, so we don’t risk wasting food or money by buying it from a warehouse club.

The bigger rice eater of the household grabs that grain wherever is convenient for him, while I tend to buy quinoa at Walmart — which carries a house brand of organic quinoa.

8. White vinegar

I’ve always found white vinegar cheapest per fluid ounce at Costco, and that’s why I bought the 1.32-gallon jugs there for years.

At some point, though, I got tired of lugging the things home, lifting them down from and back up onto the shelf in my laundry room, and trying to pour them into a cleaning bottle without spilling.

So now I just grab a 1-gallon container when shopping elsewhere, whether at a grocery store or big-box store. I found them much easier to maneuver, and the price difference is negligible.

9. Laundry detergent

Don’t get me wrong: Costco might be the best place to find affordable and effective laundry detergent. Consumer Reports recently rated Costco’s Kirkland Signature Ultra Clean the “best value” for your money. The publication rated the Free & Clear version, which I bought for years, the top pick for baby clothes.

But as with white vinegar, I eventually tired of dealing with the giant 1.51-gallon container. It was a lot to lug home, it took up too much real estate on my laundry room shelf, and like other liquid laundry detergent containers with nozzles, it sometimes leaked onto my washing machine.

During the COVID-19 pandemic, I tested out and was sold on a concentrated laundry detergent from Puracy. It works just as well, it doesn’t leak, and the refill size lasts me roughly as long as a Kirkland Signature detergent despite being much smaller. Even my husband appreciates how little space it takes up — a few square inches instead of what seemed like about 1.5 square feet.