10 Costco Shopping Mistakes That You Will Always Regret

Costco members aren’t immune to making shopping mistakes. Much like shopping at a traditional supermarket, these mistakes can lead to spending more money than saving money. For example, savvy Costco shoppers might know to buy Kirkland Signature instead of name brands but be less aware of how much money they can save buying gift cards at Costco.

Whether you’re a seasoned Costco shopper or a new member, read over these 10 common shopping mistakes and bookmark the page to keep from making them on your next Costco run. 

Regular shoppers know Kirkland Signature, Costco’s in-house brand, has a ton of grocery and household products that are just as good if not better than their name-brand counterparts. And if quality alone isn’t enough of a reason to buy, these products tend to be cheaper than name brands. 

Not sure which Kirkland Signature items you should add to your cart? Check out our list of the top 50 Kirkland products shoppers say are worth every penny.

Wait — Costco has coupons?! 

Though the warehouse club is known for not accepting manufacturer’s coupons, they do mail out an Instant Savings booklet to members advertising new sales on apparel, groceries, electronics and more each month. QR codes are occasionally printed in these mailers, so you can view even more discounts using your smartphone. 

Regular GOBankingRates readers know many of our Costco shopping roundups highlight products available online only. Take a moment to visit Costco’s website and see what’s available. (Shopping pro tip: If you lost your physical Instant Savings booklet you can view all the sales online, too.)

Buying in bulk is a great way to save money on essentials, but it’s not nearly as effective when the majority of your purchases have expiration dates. 

Be selective about the bulk items you’re buying and honest about your plans to consume or use them. A bulk set of canned soup or tuna fish can be used up over the course of several months whereas fresh produce needs to be eaten up within a few days or else it goes bad.

Don’t blindly assume that you’re getting a good deal just because you’re buying in bulk.

Julie Ramhold, consumer analyst with DealNews.com, recommends checking the unit prices of every item before you commit to buying. You might find these items are a good deal at Costco or available for a better value at a big-box retailer.

According to Ramhold, Costco’s busiest days of the week include Fridays, Saturdays and Sundays. 

Shoppers can still go shopping on these days, but they face more obstacles including long lines for checkout, difficulty finding parking spots and crowded aisles compared to other days of the week. 

Costco shoppers brave enough to withstand the weekend crowds are rewarded with an abundance of sample stations to try various foods and snacks. If you time your trip just right, you’ll make a mini-meal out of new products this way.

The key to successful sample snacking is to arrive when the stations are at their most active. According to Food Republic, this means avoiding the first hour of the day and the last couple hours of the day. Coming too early means the food isn’t done cooking or being prepared at the stations and coming too late means everything has been cleaned and packed up.

Bypassing the gift card section is common at Costco since most shoppers don’t think to go here unless gift cards are on their shopping lists. However, Ramhold recommends making a purchase because you’ll pay less than the face value of the card.

“Members can expect to save anywhere from $15 to $50 off the face value, depending on what you’re shopping for and in what amount,” said Ramhold. “A pack of four $25 gift cards to Grimaldi’s (a $100 value) is $79.99, for example.”

Do you and your partner each have a Costco membership you pay for separately? You can go ahead and cancel one of these memberships. The warehouse club allows its members to add an extra person each to their accounts as long as they’re in the same household.

If your nearest Costco club has a gas station, it’s worth the money to fill up there instead of going somewhere else. 

Not only is the fuel exceptional, but the cost is competitive, and stations are designed with a one-way traffic flow to help eliminate any gridlock before you get to the pump.

Editor’s note: Prices and availability are accurate as of July 30, 2025, and are subject to change.