3 Ways You're Wasting Money at Costco

Costco can be a great place to get good deals. It's worth going there for its $1.50 hot dog and soda combo alone. But, while bulk-buying at the warehouse club can keep your credit card bills down if you're smart about it, Costco can also be a major money trap if you aren't careful.

You should be on the lookout for these three ways you may be wasting money at Costco so you can avoid them.

1. You're not using a shopping list

The average Costco shopper spends around $150 per trip. And, for many of these shoppers, a good portion of this money is a result of impulse buys.

In fact, Reddit users regularly comment about not being able to "get out the door without dropping at least $300," and many also explain they go intending to spend a lot less money than they do (one user gave an example of trying to spend $60 and walking out with $200-plus worth of stuff).

It's not a surprise that so many people tend to just add stuff to their Costco cart. The store is set up to force you to walk past highly desirable and otherwise tempting items to get to the essentials, and it also often offers samples to boot so you're enticed to try something delicious and take a box home.

If you're not going with a list, you're even more likely to fall victim to these impulse buys since you won't have a clear idea of what you went to the store for in the first place. And if you don't go in with a clear idea of your needs, you may also end up buying things you already have at home. Doubling up can be a big problem when we're talking about bulk items that take longer to use up and require more storage space.

To stop this unnecessary spending, always shop with a list. If you see something that isn't on it, you can add it to your list for your next trip. That way, you'll have time to think about whether this is really something you want money coming out of your bank account for, and you won't just buy it because you're caught up in Costco's magic spell.

2. You're buying things you won't use up

Since Costco sells stuff in bulk, it's also easy to waste money by buying so much of something that you can't use it up before it goes bad. Let's say, for example, that you bought a 20-count variety pack of GoGo SqueeZ YogurtZ for $14.99 or about $0.75 per yogurt. This is cheaper than the 10-pack of GoGo SqueeZ at Walmart which is $8.48 or about $0.84 per yogurt.

But, what if you can't eat 20 yogurts before they expire? What if you only eat 10 and then you're done with your yogurt fix? You have just wasted $6.51 and bought an extra 10 yogurts you had to toss in the trash.

It's not worth buying in bulk unless you're sure you can use up the products before they go bad. Consider your family's current usage of a product before you buy it at Costco. If you eat something once a week, don't buy a 24-pack at Costco unless the expiration date on the item is at least 24 weeks out.

3. You're buying products before you're sure you like them

Finally, you could end up wasting a lot of money at Costco if you buy a bulk item before confirming you actually like it. It's one thing to buy one small box of cereal or one bag of a new flavored chip at your standard grocery store and find out the taste doesn't suit you -- it's another to buy an eight-count pack of chips or an industrial-sized box of cereal.

Always test out products on a smaller scale first, then see if you love them enough to buy Costco-sized amounts.

By avoiding these three common ways to waste money at Costco, you can make sure your warehouse club membership is good for your personal finances.