12 Common Mistakes Shoppers Make When Shopping At Costco

There are plenty of reasons why people love to shop at Costco. Whether it's free samples, one-stop shopping, or low prices, many Costco shoppers will say their membership is more than worth the cost. There's a reason that there are only three states without a Costco location, and when a location opens, the parking situation resembles a sports stadium on game day. And that's because shoppers know they'll get plenty of value from their membership.

But having a membership alone isn't enough to get the most value out of Costco. You also need to know how to use it wisely. These shopping mistakes show that just because something's available at Costco doesn't always mean it's the best decision for your needs. Sometimes, you might be leaving money on the table, while other mistakes might cost you valuable minutes. Here's our list of common mistakes that shoppers make at Costco, all of which can add up over time.

Most shoppers come to the warehouse to take advantage of cheaper Costco food items compared to traditional grocery stores. But not everything you find is cheaper at Costco. Loss leader stores like Wal-Mart may have an item or two that's less expensive than Costco's prices, and even traditional grocery stores can offer items at steep discounts or as a buy one, get one deal, which can work out to a better overall deal than Costco's offering.

Savvy shoppers can take advantage of this by price-checking everything they might want to purchase. In most cases, Costco will have the better buy, especially on name-brand items. But if you aren't wedded to a specific brand, using Costco exclusively can lead to you spending more than you otherwise would on the same type of item. You might find a great price on Diet Pepsi at Costco, but if you don't care what kind of soda brand you drink, getting the store-brand diet cola at your local grocery store can be the better buy.

Costco consistently offers generous deals on name brand products. Because you're buying in bulk, Costco can afford to offer large discounts from the biggest names in manufacturing. But Costco's own store brand, Kirkland, usually offers the biggest savings over traditional grocery chains. If you're only buying brand names at Costco and ignoring Kirkland products, you're leaving money on the table.

From granola bars to tuna to pistachios, Kirkland products are known to be high-quality options at steep savings over brand-name versions of the same items. In some cases, the brand name product and the Kirkland product are the same exact thing, just with a different package. On cranberry juice, for example, Kirkland doesn't even try to hide the fact that it's Ocean Spray; both labels are featured prominently on the package. Other products might be more subtle, but you're usually getting name-brand quality in a different package when you buy a Kirkland product.

With roughly half of American shoppers willing to buy store brands, this is a mistake fewer shoppers make every year. If you spot a deal on a Kirkland product that you're likely to use, it's worth trying out. In most cases, you won't even notice a difference in taste or quality compared to what you usually buy.

There's an episode of "The Big Bang Theory" where Sheldon points out what Penny could save if she bought in bulk. To prove his point, Sheldon says Penny could purchase tampons in bulk, because they won't spoil and she'll be using them for the next 30 years. Of course, Penny incredulously responds, "You want me to buy 30 years' worth of tampons?"

Sheldon might have a point about buying in bulk, but Penny's correct that it only makes sense if you have both the storage space and the need for the product. A great deal on a Costco item only makes sense if you can actually use it. Condiments only last so long, so the bulk strategy might not work out for multiple reasons. Ketchup, for example, expires within two years unopened and six months once you open it. Even if you will use all of a product, such a deal can have drawbacks. Costco's Grill Pack can give you all you need for a cookout, but if nobody in your house eats relish, you might be overpaying for just the ketchup and mustard.

Even with products that seemingly won't spoil, such as paper products, there's a shelf life before they lose efficacy. Toilet paper, for example, isn't as effective after three years on the shelf. Even Sheldon's tampon example doesn't work: they can go bad in five years.

Have you ever noticed that Costco parking on the weekends tends to be as complicated as finding parking at a stadium? There's a reason for it: most people grocery shop on the weekends. That means large crowds in the parking lot, packed aisles inside the store, and fewer selections for your dollar.

None of that is conducive to getting what you need and getting out. Instead, you're setting yourself up to spend more time in each aisle, and the more time you spend, the more likely you are to buy something you don't really need. Additionally, you're wasting time in long lines, which can ruin your plans for Saturday or Sunday. Unless you're going for the food court, you don't want to deal with long lines at Costco.

So when should you shop at Costco? Wednesday tends to be the lightest day at Costco, but there's another great reason to shop Costco on Wednesdays: Most grocery stores either start new sales or end old ones on Wednesdays. If you comparison shop — which you should — you can compare Costco prices to the new ads on Wednesdays. That allows you to get the best bang for your buck while enjoying easier shopping, a win-win.

One of the best things about Costco is the abundance of free samples. If you're a regular Costco shopper, you've probably gone shopping for the purpose of getting a mini-meal out of the sample stations. You might even have committed the unintentional sin of being too nice and taking something you didn't really want to buy because you felt guilty.

But did you know that sometimes, the free samples at Costco aren't available at all? If you're shopping in the first hour the store's open or in the last hour or two of the day, you're likely to miss all of the samples. The sample stations take time to set up in the morning, and they close down before the final hour of the day. If you're shopping in the last hour of the day, you aren't going to find any options for samples, and you might not find any options for the products you like at all.

If you want to try before you buy, your best bet is to go just after lunchtime. That's when the highest number of employees are on the sales floor. If you really want to make the most of your Costco sample experience, try going on Saturday. And don't be shy about taking two or more of something — they're free!

Gift cards can be a great way to spread your Costco savings to your other favorite retailers. That's because Costco usually buys gift cards from retailers at a discount and passes them on to its shoppers. Usually, you'll save about 20% to 30% on gift cards at common establishments in your area. If you know you'll go there, why not chop a few dollars off your total spending?

Costco doesn't limit gift card shopping to restaurants, either. You might find $100 worth in Hulu credit for $90 one month, or you might find a $500 Southwest Airlines gift card for $450. Both of those can be great ways to save on things you were probably going to buy at some point in the future. In the case of the Hulu example, you're essentially getting one month off your bill by paying for several months at once. With the Southwest tickets, you'd have your next vacation wholly or partially paid for; it's just a matter of choosing the dates and buying when the tickets go on sale.

Even if you only use Costco gift cards to get $100 worth of delivery pizza for $75, that's still a substantial savings over what you would have paid. It's always worth taking a glance at the gift card section to see if you spot something you'll use.

The Costco hot dog is one of the cheapest deals around. But did you know that there's a code to Costco's other prices that can tell you when something's on sale? The numbers that Costco uses to end its prices actually serve as the store's code, and savvy shoppers understand that the numbers can actually alert them to good deals.

If a price ends in .99, there's no need to rush to buy it; it's a standard price. Anything ending in .97, however, is a sign that an item's both on sale and though possibly only available at that location. These are usually clearance items that Costco needs to get rid of, so now's the time to take advantage. Many other numbers mean it's a brand-name discount. These are deals from the manufacturer, and Costco's passing the sales on to its customers. These prices usually end in .39, .49, or .79, which are designed to catch your attention. Even rarer are the .88 or .00 prices, which are designed to move quickly. These have been marked down by a manager, so they've received direct orders to move them now.

The biggest thing to look for is the dreaded asterisk. The asterisk is the biggest sign of any that you've found a sale and you've got to buy right away. An asterisk on a pricing sign means that it's not going to be restocked, so once that supply is gone, it's gone for good.

Costco is notorious for not honoring another store's prices. It doesn't matter if another store had the same item on sale, there was a manufacturer coupon or the discount came another way: you can't price match with another retailer.

But price matching at Costco itself? That's a different story. Let's say you went ahead and bought something at the standard price, and you find the same item on clearance a week later at the same Costco location. All you have to do is bring in your receipt and prove that you paid the higher price for that item, and Costco will give you the new sale price. As long as you bought the item within 30 days, Costco will price match anything that you can show you bought at a higher price than what's now available.

That's why you should always save your receipts once you get them checked. You never know when you might find a deal on something you buy regularly, and paying attention to details can save you money well after your initial purchase.

In a lot of cases, you're going to find the best buy for your needs at Costco. You're paying for your membership to save on different products, so it's natural to assume that the best price is the best buy.

But some items just aren't meant to be bought at Costco if your family doesn't use them very often. For example, getting two packs of bagels for only slightly more than buying one at the grocery store seems like a great deal. But if four of your bagels go bad before you've had a chance to eat them, you would have been better off buying only one pack and waiting to get a second one.

Buying too much fresh produce from Costco also falls into this trap. In fact, it's the most common offender because most people can't use that much produce and don't have a place to store it before it rots. The best strategy is to know your family and know your storage space.

If you know you're going to consume something perishable before it expires, by all means, get it at Costco and enjoy the savings. But if you're hesitant about whether your family needs that much of something, you might want to buy smaller at the grocery store. You'll likely save money in the long run that way.

At $60 a year for a membership, Costco's membership cost is already a pretty good deal. That comes out to just over $1.15 per week, and most shoppers easily make that up with each trip they make to Costco. But for a single person, there's a way to make that price even more affordable for you.

Costco gives members two membership cards when they join, with the idea being that most people will use them for themselves and their spouse. But there are no restrictions on how someone uses their second membership card. Since only members can shop at Costco, two single friends could divide the cost of their membership between them. Splitting the cost gives both people the same benefits for just $30 a year, which can more than make it worth it to buy staples at Costco.

Even if someone doesn't think they plan to shop at Costco very often, the savings on staples can make it worth the occasional trip. Only having to buy toilet paper and laundry detergent twice a year can make budgeting much easier.

Costco has two levels of membership, the standard and the Executive. The Executive membership costs double the price of the standard membership, but it comes with an important perk: 2% back on all purchases from Costco. Those become reward dollars, which never expire.

For people who shop at Costco regularly, upgrading to the Executive tier can be worth the extra money. Getting 2% back means that if someone spends $250 per month at Costco, upgrading to the Executive tier will pay for itself, because they'll get back the $60 per year that you're charged to upgrade as rewards. Even if they only spend $200 per month at Costco, they'd still be getting the Executive tier for just $12 extra.

Getting cash back and getting access to extra discounts on travel and other perks can be worth it for shoppers who have established loyalties with Costco. The Executive tier also offers discounts on Costco's travel program, which can mean much cheaper vacations. If someone knows they'll be doing a lot of shopping at Costco, upgrading to Executive makes a lot of sense.

The pharmacy is unique at Costco, as it's the one thing non-members are allowed to use at Costco. If someone doesn't have a membership, they can still visit the pharmacy and save on prescriptions. In some cases, non-members can find significant savings at the pharmacy over other options in the area.

But members are privy to even better deals than non-members. Although non-members can pick up prescription drugs at Costco, they cannot take part in the Member Participation Program, which unlocks even larger savings for Costco members. Members can sign up for this program and check the cost of their prescriptions before they ever come to the warehouse, so they'll know in advance if they're getting the best deal.

Along with prescription drugs, Costco is one of the best places to stock up on over-the-counter medicines. Buying a larger package of medicines such as Mucinex or Pepto Bismol can ensure a full supply that won't run out anytime soon.