Anyone with a Costco membership knows that the warehouse store is a great place to score some bargains. But, unfortunately, even Costco shoppers can't win 'em all, and there are some things—though not too many—that you're probably better off buying somewhere else. Savings experts and savvy Costco shoppers alike agree that Costco isn't the best place to stock up on cereal. Find out more Costco items that you think will save you money, but won't.

There's nothing wrong with Costco's cereal options; in fact, they're pretty much the same as what you can get at any other grocery store. The catch, though, is that you'll probably save more money in the long run if you get your Honey Nut Cheerios fix from those other grocery stores instead. As The Krazy Coupon Lady founder, Joanie Demer, told CNBC, you're better off keeping an eye on the sales at your local grocery store. She claims that different cereal brands tend to go on sale at different times, often on weekends. "One week it's going to be General Mills, another week it will be Kellogg," she said. Snatching up your favorite cereals when they go on sale will save you lots of cash. Funnily enough, you might want to skip buying cereal's common counterpart, milk, at Costco, too—here's why.

Still not convinced, Costco fanatics? Money-saving expert Melea Johnson broke down the numbers for Money magazine. Costco's cereal prices shake out to around 17 cents per ounce, but you can easily get cereal on sale at the supermarket for 13 cents an ounce. Johnson says that $1.50 is a reasonable grocery store sale price for an 11-ounce cereal box. Meanwhile, a two-pack of 20-ounce Cheerios boxes will set you back $7 at Costco. Never fear, though, Costco enthusiasts: There's still a whole plethora of items that make that membership worth it. Learn the 12 Costco items you definitely shouldn't be without.