3 Ways You Might Waste Money at Costco Rather Than Save Money

A basic Costco membership costs $60 a year these days, while an upgraded Executive membership costs $120. The Executive membership lets you score 2% cash back on your Costco purchases, so if you shop there often, it's easy enough to make back that upgrade fee.

Typically, people join Costco with the intention of saving money. And Costco's low prices certainly make that possible, even when you account for the membership fee you're shelling out. But if you keep doing these things, you might end up wasting money at Costco rather than saving it.

1. Making too many impulse purchases

Costco tends to rotate a fair amount of its inventory on a seasonal basis. In the spring and summer, you'll often see outdoor toys and swimwear. In the fall, you'll see cozy fleece jackets and Halloween costumes. And during the winter, Costco's aisles tend to be loaded with holiday decorations, and the toy section commonly grows more robust. 

All of this extra seasonal inventory can open the door to temptation. After all, how can you say no to a gourmet chocolate gift basket during the holidays or an inexpensive flannel shirt to complement your fall wardrobe? But if you keep giving in to impulse purchases at Costco, you're going to end up wasting money -- and you might sorely regret that after the fact.

A better bet? If you want to keep your Costco spending in check, make a list of the items you need before heading over, and only visit aisles that have an item on your list. The simple act of staying out of those seasonal sections could be a huge money-saver.

2. Buying food you end up throwing out

Many people join Costco for the option to buy groceries in bulk, since that can be a huge source of savings. But if you keep having to throw out food purchased at Costco, then you aren't doing your finances any favors.

Before you buy bulk grocery items, think about whether they really align with your family's eating patterns. It's tempting to buy a bulk pack of spinach when the cost for two pounds at Costco is the same as the cost for 10 ounces elsewhere. But if your family eats spinach once every two months, that's probably not a very good buy.

Also, check expiration dates when purchasing bulk items at Costco, as some products have better ones than others. If you're buying a large bag of chips, for example, you may find that the packages at the front of the shelf have a two-month expiration, whereas the ones in the back have dates farther out.

3. Not using your membership

Unplanned Costco buys and tossed food can result in wasted money. But one of the biggest wastes you might also fall victim to is simply not using your Costco membership at all. You might fall into that trap if your nearest Costco is still many miles away, or if your schedule is such that you just can't make it over there during operating hours.

If that's the case, though, you can look at buying groceries and other products through Costco.com. Although prices tend to be lower in stores, you can still reap savings with online orders. And that way, you're also saving some money on gas.

But ultimately, it's important to be realistic about your Costco shopping. If you realize you're not going to make it to the store more than once or twice a year, then it may not be worth the money to hang onto your membership. A better bet may be to just tag along with a friend on the rare occasion you're able to pay Costco a visit.

Costco can be a major source of savings. Just make sure you're reaping those savings, too.