5 Items I Always Buy at Costco

It took my family a little while to figure out how best to use our Costco membership. But we've figured out a handful of purchases that are a good deal for us, making the membership more than worth it.

Here are five things we always buy at Costco to keep our finances on track -- plus one way avid Costco shoppers can save even more money.

1. Kombucha

Price: $16.16

I was late to the kombucha game, but I'm all in now, and the only place I will buy it is Costco. My favorite is the ginger lemonade, and the per-bottle price of the gut-friendly drink costs far less than at many other stores. An eight-pack of Kirkland's organic kombucha is just $16.16. That's about $2.02 per bottle, half the nationwide average price of a 16-ounce bottle.

If you don't have a Costco membership, you can still find great deals on kombucha (and nearly anything else) using a deal app.You can shop for grocery items, scan barcodes in the store to compare prices, and even set alerts to find out when there's a price drop.

2. Allergy medicine

Price: $23.89

Seasonal allergies can do a number on my family; apparently, we're not the only ones. About one-quarter of U.S. adults suffer from seasonal allergies, and it's becoming more common among adults.

One of the best ways my family has found to fight against pollen storms is using Kirkland brand nasal spray, comparable to Flonase brand. A five-pack of the spray costs just $23.89, which is $15 cheaper than a three-pack of similar spray at Target.

3. Gas

Price: $2.77 per gallon

In addition to its free samples and $1.50 hot dog and soda combo, Costco has earned a reputation for offering discounts on gas. In my neck of the woods, Costco gas costs about $0.18 less per gallon than at my closest gas station.

You can check the price of Costco's gas in your local area on Costco's website to see if it's a good deal near you. The good news is that AAA has rated Costco gas a top-tier fuel, so you don't have to worry about the quality you're getting for those discount prices.

You can save more than $100 annually buying Costco gas versus going to a regular gas station, which more than covers the cost of a $60 Costco membership.

4. Maple syrup

Price: $14.99

My kids eat waffles at least twice weekly, so we always have maple syrup on hand. If they had their way, it would certainly be every day. Unfortunately, I don't eat waffles as often as they do, but I use Costco's syrup as a sweetener for my iced coffee.

A one-liter bottle of Kirkand's maple syrup is just $14.99, while a slightly smaller bottle of Walmart's maple syrup costs $15.98. That's a good enough deal for us to stock up on syrup for the next round of waffles.

5. Protein powder

Price: $36.99

We use protein powder for morning shakes and afternoon fruit smoothies nearly every day. We'll even sprinkle some in when we make the kids' pancakes. With all that use, we quickly go through a large tub of protein powder.

Costco is a great place to buy it because you can get a large 2.7-pound container of organic plant-based protein for $36.99. The same tub of powder is listed for $49.78 on Walmart's website.

The best credit card for Costco shoppers

If you frequent Costco's aisles regularly, you may want to consider the Costco Anywhere Visa® Card by Citi. You can earn up to 2% cash back on purchases in Costco stores and online.

And if you're looking for even more ways to save, consider a Costco Executive membership (which costs $120). You can combine the 2% cash back from the Costco credit card with the 2% back from Executive membership purchases to bring your cash back earnings to 4% on most purchases.