Here's Why You Keep Overspending at Costco -- and What to Do About It

One of my favorite things about shopping at Costco is that you never know what you're going to find. You might run in for milk, eggs, and meat only to come home with a cozy fleece jacket or awesome toy bundle for your child's birthday. 

But Costco's rotating inventory can be a mixed bag. It's awesome when fun new items hit the shelves, but it's not so awesome when those extra purchases add up and bust your budget. 

Trust me -- it's a trap I've fallen into many times. And the worst part? Costco is doing this to me on purpose.

Well, it's not just me. One of Costco's general strategies is to keep introducing new products, so shoppers are tempted to spend more. 

Costco's new CFO Gary Millerchip even admitted to this during the company's most recent earnings call by saying, "You've heard the phrase, people come in to spend $100 and walk out with $300. That's because our buyers and our operators do a great job in making the warehouses exciting…when {customers} come in there and do their basic shopping, they pick up a few additional items that just compel them at the time."

But while Costco may be great at enticing people like me and you to spend more than planned, we don't have to be victims. As a long-term Costco shopper, I've picked up some habits that help me avoid impulse buys. Here are some of the moves you can make to stop overspending at Costco.

1. Don't enter any aisle that doesn't contain an item on your shopping list

Any Costco aisle you don't need is an aisle you shouldn't walk through during a shopping trip. Period. 

Some people like to come in, walk around, and see what's on the shelves. One thing I have going for me is my busy schedule. When I run to Costco, it's usually an in and out sort of deal because I need to get back to my job or another task. So that helps me stay out of aisles I don't have to visit. 

But as a general rule, you should adopt a similar strategy if you commonly make extra purchases at Costco. Otherwise, you, too, might one day find yourself saying, "This fondue pot is just what I need right now." Spoiler alert: It's still in the box. 

2. Walk through the front of the store as quickly as possible

Costco tends to strategically place sale items at the front of the store so that when you first walk in, it's like "Bam -- gotcha." I've learned to walk through that area as quickly as possible and not look too closely at what's on sale to avoid temptation. 

If you happen to spot a sale item at the front of the store you're tempted by, at least finish your planned shopping first. 

This strategy often works for me because to get back to the front of the store after filling my cart, I need to walk past the checkout aisles. Usually, when I see how long the wait is to check out (even at off-peak times, there's always a wait), I'm motivated to just get in line rather than go back out of my way for a sale item I wasn't planning to get in the first place.

I've been to many Costco locations and their layouts all tend to be similar. So chances are, if you manage to walk on by from the start, you won't make it back to the front of the store. 

3. Only bring cash

The downside of not using a credit card for Costco purchases is missing out on earning cash back. The upside is that you can't spend money you don't have. So if you leave your credit cards at home when you visit Costco and only bring enough cash to cover your planned purchases, you take the option to overspend off the table.

Of course, Costco prices aren't set in stone. So if you're going to bring cash, add a buffer. But if your normal weekly grocery haul costs $100 and you bring $120 in cash, you're limiting your option to buy something unplanned to a large degree. And this way, if your groceries come to $107, you won't have to put back something you needed due to not bringing enough money.

As someone who once ran into Costco for seven specific grocery items and came home with an inflatable kayak, I can sympathize with the idea of being lured into spending more than expected when shopping. But the best way to avoid being tempted to buy extra Costco buys is to limit the aisles you visit, rush through the front of the store, and, if necessary, shop only with cash.