The 8 Biggest Mistakes You Might Be Making While Shopping at Costco

Costco is known for its bulk buy deals and wide selection of products, from food and groceries to toiletries and office supplies, and more. However, it’s easy to get carried away and make some common mistakes that will negatively impact your wallet, purchases, and overall experience.

That’s why it’s a good idea to go into the club store with a game plan in place where you know what you want to buy, the products you should always avoid, and the best and worst times to shop at Costco. (FYI: Avoid going on weekends, specifically Sunday since that’s when you’ll find the largest lines and crowds—if you go on a weekday and during corporate hours, you’ll have the store to yourself, use your time most efficiently and have access to the greatest selection of products.)

These are the top mistakes you could make at Costco, so keep them in mind the next time you’re walking down the aisles.

1. Buying Foods in Bulk You Won’t Eat in Time

Costco is the perfect place for buying canned goods and beverages in bulk for affordable prices and deals; however, you shouldn’t buy large quantities of foods you can’t consume in time just because they’re cheaper. “Buying large quantities simply because the price per unit is lower is a common mistake,” says food blogger, chef, and home expert, Alex Bayev.

That means, don’t buy boxes of cookies or produce that’ll grow stale or rot before you’ve had a chance to eat them. “Instead, plan your bulk purchases around items with a long shelf life or those you can freeze for later use,” Bayev suggests. Think realistically to avoid food and monetary waste.

2. Underestimating Kirkland Brand Products

Don’t avoid Costco-branded items, assuming they’re inferior to more well-known brands. “Some shoppers may overlook Costco's house brand, Kirkland Signature, assuming it's of lower quality; however, many Kirkland products are actually produced by the same manufacturers as big-name brands and offer great quality at a lower price,” Bayev explains.

If you’re skeptical, make sure to compare prices and check reviews to see other customers’ thoughts—if the Kirkland reviews are excellent and will save you money, don’t make the mistake of skipping over them.

3. Forgetting Manufacturer Coupons or Your Costco Card

Many shoppers are unaware that Costco accepts manufacturer coupons, which can produce some great savings on certain products. “Before your trip, check if any of your planned purchases have manufacturer coupons available and bring them along,” Bayev says. This will help you save as much as possible (always a nice perk!), and you won’t feel flustered when at the store, since it’ll all be readily available and accessible at check-out. The same goes for your Costco card. Always use it at check out to take advantage of savings. “Oftentimes, people forget [to use] their card when making a purchase, and this is a big blunder that many Costco shoppers can make that can lock them out from many perks which come with the card,” says Elice Max, Co-Owner and Marketing Director EMUCoupon. The card comes with many exclusive perks, including chances to win fully paid vacations.

4. Not Taking Advantage of the Organic Section

Sure, it’s fair to say that most people don’t think “organic” when considering Costco and what kinds of products they’re best known for carrying. However, there’s actually a well-stocked organic department with some high-quality options that are worth browsing and trying at home.

“Some people might assume warehouse clubs like Costco won't have a good selection of organic products, but Costco offers a wide variety of organic items, often at lower prices than traditional grocery stores,” Bayev says. If you prefer organic, give Costco a try before choosing to do two separate grocery store trips that’ll cost you unnecessary time and expenses.

5. Shopping Only the Middle Sections

Common items are found in the middle sections or center of the grocery store, and Costco’s no exception. “While the center may have attractive items like seasonal offerings, electronics, and boxed sets not found in other grocery stores, these products are strategically placed to grab your attention rather than help you save money,” says Michaela Melo, marketing expert at Musician Authority.

“The highest foot traffic occurs in the middle sections, and Costco positions items that appear more enticing and you’ll more likely impulsively add to your cart,” Melo explains. Be wary of the middle and make sure to browse the back and side aisles, Melo suggests. You'll have better luck finding substantial discounts and deals on products there due to less competition, too.

6. Heading into Costco Without a Shopping List

Without direction, you’re more prone to impulse buys due to hasty thinking and temptation. To avoid this, make a shopping list at home and stick to it. “Spend 5 minutes at home and create a comprehensive list of the items you genuinely need and are worth buying at Costco, and consider item size, quantity, and storage space when making your list,” suggests Greg Larkin, Managing Editor of Costco Food Database.

Even with a shopping list, Costco doesn’t have to be a get-in and get-out shopping experience—there’s no need to rush or make it less enjoyable simply by having a game plan and being more mindful of your necessities and budget. “I always have one spot on my shopping list called ‘Costco Deal,’ which allows me to shop the aisles still and make one random impulse purchase,” Larkin says. “Just make sure to write down an upper price limit for the item,” Larkin notes.

7. Shopping at Costco When Hungry

As with any grocery store trip, if you go into Costco on an empty stomach, you might spend more on items you don’t need or want. Fuel properly and have a snack before arriving to shop more clear-headed and purposeful. “Costco can be a warehouse full of bad decisions if you are hungry,” Larkin says, suggesting even stopping at Costco’s food court prior to hitting the aisles to grab a quick bite.

You can spend $1.50 on a hot dog at the food court before shopping, for example. “It’s better than coming home with 28 Jumbo Corn Dogs or 90 Mozzarella Sticks you really didn’t want and don’t fit your diet,” Larkin says.

8. Ignoring Items That Are on Sale

You may overlook items on sale, thinking that you’re already scoring savings just by shopping at Costco to begin with. That’s a big mistake, though, since you’re missing out on extra savings! Their sale items are practically steals for savvy shoppers. “Sale items are often 25-30% off of Costco’s already discounted prices, and it’s well worth stocking up if you have the storage space,” Larkin suggests.

Be mindful of expiration dates—Larkin recommends checking the expiration dates first and loading up on non-perishables, such as peanut butter, sardines, and spaghetti sauce, which have longer shelf lives.