Unless you're going shopping alongside a member, you typically need your own paid annual membership, a basic version of which costs $60. Costco also offers a Gold Star Executive Membership that costs $120 a year and offers a 2 percent cashback reward up to $1,000.
Is a membership worth it? Generally, it would be, if you spend at least $600 a year there, Joanie Demer, co-founder of The Krazy Coupon Lady, tells CNBC Make It. Other experts suggest that it could make sense if you have kids, pets, prescriptions and/or a car.
Or consider trying out these hacks that could help you skip the membership and still some save money.
Ask someone with a membership to pick you up Costco Cash Card next time they're shopping. It's the store's version of a gift card and it will get you in the door whether you have a membership or not, Demer says.
No need to feel guilty: "Members and non-members may use the Costco Cash Cards to shop at any Costco location in the United States, Puerto Rico, Canada and online at Costco.com," according to the terms and conditions of the card.
This hack has been around for years, and Demer doesn't expect Costco to get rid of it anytime soon. "They're extremely confident in the offering and in the addictive properties of the Costco shopping experience. So that's why they still have it and it's working out for them," she says.
This hack is best for people who only shop at Costco occasionally.
You don't need a membership to shop at Costco.com.
Going this route, however, does have some drawbacks. First, you'll have to pay a 5 percent surcharge as a non-member. Second, prices may be lower — up to 20 percent lower in some cases — when you shop in-store. And a lot of items are not available, including many fresh groceries.
Costco.com offers 2-day delivery for its members, with free delivery on orders of $75 or more. But non-members will need to make do with 3-5 day shipping.
Non-members can also have their groceries delivered from Costco via Instacart. The grocery delivery app lets personal shoppers to pick out your groceries and deliver them to you. It's generally available in cities around the country, but you can check out the full list of available metros online.
Again, prices through Instacart are higher than those found in the store, according to Costco. And you also will have to pay service and delivery fees, which vary depending on your location.
But you can choose from about 2,000 available grocery items, and same-day delivery, sometimes in as little as two hours, is available.
Because of state and local laws, you can buy alcohol and prescriptions at Costco without a membership, according to the Krazy Coupon Lady. That includes immunizations such as flu shots: Costco is among the cheapest places to get those done if you don't have insurance.
If your local Costco has an optical department, you also can book a cost-effective eye exam with an on-site optometrist without a membership. And if you're hungry afterwards, you can swing by Costco's in-store food court. Anyone paying cash can chow down on Costco's $1.50 hot dog combo.
Depending on your circumstances, even something that's well-priced at Costco may not make sense for you. Because Costco often sells products in bulk, you need to be able to eat any perishable food before it goes bad, for example.
"I think people feel like, 'Because I'm paying for a membership, everything here is a great deal,'" Demer says, but that's not actually the case. Even if you head to Costco regularly, you need at least one other place to shop as well: "Otherwise, I'm willing to bet you're buying enough things that aren't good deals that you're kind of wasting the savings you're acquiring."
If you're a devoted coupon clipper, you may be better off, in many cases, at your local grocery store. That's because Costco doesn't accept manufacturer coupons, although they do have their own coupons and promotional offers.
And if you do a lot of online shopping, consider Amazon's Subscribe & Save. You don't need to be an Amazon Prime member to take advantage of this service. It lets you save up to 15 percent on items, many of them sold in bulk, that you can select to be delivered automatically at a desired interval.
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