9 Things That Are Always Worth Buying at Costco

Stick to items that won't expire in the back of the pantry for the best results.

If you've ever thrown away half a gallon of ketchup because you got a little carried away at Costco, you know that not every bargain buy ends up saving you money. Sometimes, that bulk package becomes more of a chore than a delightful deal.

But not everything you buy in bulk has to become a battle to the end. If you buy strategically, Costco and other warehouse stores really can save you money.

The key word here is "strategic," however. Knowing what to buy -- and what to avoid -- can make the difference for your next Costco trip, as well as your bank account. Here are nine things that are always worth buying.

1. Vanilla extract

It's easy to underestimate the importance of quality vanilla extract until you forget it in a recipe (or, worse, use a bad knockoff "flavoring"). While the good stuff is often more expensive than the imitation, you can usually save a few bucks picking it up at Costco. 

Even better, you don't have to worry about using it up before it expires -- because it doesn't. According to McCormick, pure vanilla extract can last indefinitely. In fact, it may even develop a richer, more intense flavor as it ages.

2. Maple syrup 

Pure maple syrup is objectively superior to the sugar-water substitutes they sell as "pancake syrup" in grocery stores. Sadly, the price is -- not. Maple syrup can be twice as expensive (or more) than the alternative, but you can cut your per-ounce cost by picking it up at Costco.

Unopened, maple syrup can sit in a cool, dark place indefinitely. After you open it, how you store it will determine its shelf life. In the refrigerator, you'll get at least a year. Freezing your syrup can make it last even longer.

3. Frozen fruit

Unless you're feeding half the neighborhood, buying fresh produce at Costco is usually a no-no. But you can get quality, organic frozen fruit for a fraction of the cost you'd pay in the grocery store. Frozen fruit can last 12 to 18 months in the freezer when purchased frozen and stored in an airtight bag.

4. Baby formula

Although an open can of baby formula has a short shelf life -- about a month in most cases -- chances are pretty good you'll plow through it long before you have to worry about expiration dates. And it's that rate of use that makes finding an affordable option important. Costco's Kirkland brand formula (the house brand) is significantly less expensive than many alternatives.

5. Gift cards

Gift cards are as good as cash for the retailers that offer them, but they have one extra benefit: You can buy them at a discount at Costco. The warehouse retailer often offers gift card "packs" for popular brands at 80% to 90% of face value. While you shouldn't buy gift cards you'll have a hard time using just because they're a bargain, it can be a great way to stock up for holiday gift giving. I also like them for purchases I can't otherwise maximize with credit card rewards!

6. Dinner party staples

There are many things you should avoid buying at Costco because of expiration dates. There's only so much cheese you can use in any given week, afterall. But the big exception here: parties. If you're getting ready to host a big dinner party or family get-together, all those rules go out the window.

Bulk buying food for a party can easily save you money versus shopping at the regular grocery store. Everything from meat to cheese to chips can be had for a lower price-per-ounce. Just be sure you can store any leftovers. Or, even better, send everyone home with a goodie bag!

7. Gas

When you're looking at $4 and up for a gallon of gas, every penny you can save can make a difference. Costco gas prices are regularly at least $0.10 to $0.30 a gallon cheaper than other stations. Depending on how often you fill up, gas savings alone pay for half -- or all -- of your yearly membership fee. Double down by using your favorite gas rewards credit card to earn bonus rewards on every dollar.

8. Rotisserie chicken

The only thing better than getting a good price on dinner? Not having to cook it. You can hop into Costco and get a ready-to-eat rotisserie chicken for just $4.99. What's more, it's pretty likely this popular dinnertime staple will continue its affordability for a long time; Costco hasn't increased the price on their rotisserie offering in more than 10 years.

9. Food court hotdogs

If there's anything more iconic at Costco than their hotdog and soda deal, I don't know what it is. The warehouse store has offered its classic combo for just $1.50 since 1984. And even in the face of recessions and inflation, that price isn't going up anytime soon. Costco co-founder and former CEO Jim Sinegal recently made headlines for his… enthusiastic confirmation that the beloved hotdog combo would maintain its $1.50 price tag -- or else.