Don't Fall Victim to These 3 Expensive Costco Traps

Many people have a single goal in joining Costco -- to save money. Ironically, Costco forces customers to spend money for a membership -- $60 a year for a basic (also known as Gold Star) one and $120 for an Executive one offering 2% cash back on purchases. But if you're paying $60 a year for Costco access and you enjoy a weekly savings of $10 on groceries, you're technically up $460 after 52 weeks despite the membership fee.

That said, the more strategic you are in your Costco shopping, the more savings you'll be able to reap. It pays to avoid these potentially expensive traps.

1. Paying more for online purchases

One of the things I like least about visiting Costco are the crowds. Even when I shop at seemingly off-peak times, like when the store first opens and there aren't even any samples out yet, I still find myself waiting in long checkout lines and having to bump shopping carts with fellow customers to get down the aisles.

I'm sometimes tempted to shop on Costco.com instead of going to the store. But there's a big reason I usually don't -- it's more expensive.

Many of the items you'll see on Costco.com have the cost of shipping and handling built into the price. But that means you're looking at paying more than what you would at your local store.

Of course, if you don't have access to a car or have a reason you can't get to Costco in person, like an injury, then by all means, do your shopping online. Otherwise, don't assume you're getting the best deal on Costco.com because there are no shipping charges. You're paying for shipping, all right -- just not in the way you think.

2. Giving into front-of-store impulse buys

Ever notice how the front of Costco is loaded with random sale items that don't tend to have anything to do with each other? Just the other day, I walked in and saw discounted toothpaste, beach towels, and gardening supplies.

But you should know that giving into front-of-store impulse buys at Costco could make your shopping trips more expensive than they need to be. A better bet is to walk past the front of the store and stick to a specific list.

Remember, the items you'll see at the front of Costco aren't always limited-time deals, even though they're often billed as such. Last week, I impulse-bought toothpaste because it was on sale and I was running low. But in the grand scheme of unplanned buys, dropping $10 and change on toothpaste is hardly reckless.

On the other hand, it took self-control to not buy some cheap beach towels, since some of ours may inevitably get lost during the summer (thanks to my kids). But since I know Costco will probably continue to have beach towels in stock for the next couple of months, I didn't grab the deal.

I figured it makes more sense to get through the summer and see what happens. Then, if I still need more towels, I see if Costco puts any on clearance as the season is winding down.

3. Paying a surcharge for online orders as a non-member

Did you know that you actually don't need to be a Costco member to shop on Costco.com? While a membership card is required to enter the store, online shopping at Costco is open to everyone.

But if you don't pay for a membership, you'll face a 5% surcharge on your Costco.com orders aside from prescription drugs. And paying a series of surcharges could exceed the cost of a membership itself.

Let's say you place a $120 Costco.com order every month. If you're being charged $6 more each month, you're paying $72 extra for your purchases. Why do that when you can just get a membership for $60?

And remember, there may be a month when you decide to take advantage of a deal Costco is running on a big-ticket item, like a laptop or TV. But for a $1,500 item, you're paying $75 more on that single purchase.

Shopping at Costco saves me money regularly. It should save you money, too. And a good way to make sure that happens is to steer clear of these traps.