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Warehouse clubs promise big savings, but which one delivers more on an ordinary grocery run? To find out, I carried the same grocery list into both Costco and Sam's Club and compared prices category by category. Each store has its own private-label brand, Kirkland Signature at Costco and Member's Mark at Sam's Club, so the comparison often came down to generics going head to head.
A quick note before we dig in: prices and availability are subject to change and may vary by location. With that out of the way, here is how all 10 categories shook out, along with the clear winner at the end.
Prepared foods and bakery buys
Prepared foods were nearly a dead heat. A rotisserie chicken ran $4.99 at Costco versus $4.98 at Sam's Club, and chicken salad came in at $5.99 per pound at Costco against $5.98 per pound at Sam's. The differences are pennies, but those pennies add up over time.
Bakery buys leaned in Sam's Club's favor. French baguettes were $4.46 at Sam's versus $4.99 at Costco for a pack of two. Cookies cost $19.93 for 84 at Sam's compared with $22.99 for 60 at Costco, and croissants were $5.96 per dozen at Sam's against $5.99 at Costco. Across the board, Sam's offered slightly better value in the bakery aisle.
Pantry staples and everyday essentials
Everyday essentials favored Sam's Club as well. A 67.6-ounce bottle of Kirkland Extra Virgin Olive Oil was $20.99 at Costco, while a comparable 68-ounce Member's Mark bottle was $17.98 at Sam's. Canned goods told a similar story. Costco offered a 12-count of Kirkland Organic Tomato Sauce in 15-ounce cans for $13.49, while Sam's, which had no organic option, sold the same quantity of conventional sauce for $9.68.
Frozen foods continued the trend. A four-pound bag of broccoli florets cost $9.99 at Costco versus $6.68 at Sam's. Beverages were the closest call of all: a 40-count of generic purified water in 16.9-ounce bottles was $3.98 at Sam's, with Costco coming in just one cent more.
Desserts, meat, dairy, and snacks
Desserts gave Sam's another win. A four-quart tub of Kirkland Super Premium Vanilla ice cream was $12.99 at Costco, while a five-quart tub of Member's Mark vanilla was just $8.12 at Sam's, offering more product for less money.
Meat and poultry favored Sam's too. Boneless, skinless chicken breasts were $2.99 per pound for Kirkland at Costco versus $2.88 per pound for Member's Mark at Sam's. Dairy was the rare category that landed in Costco's column on sticker price: an 18-ounce President Triple Creme Brie was $6.99 at Costco, while a 19.6-ounce President soft-ripened brie was $7.64 at Sam's. Factoring in the larger size, though, it was essentially a tie.
Snacks closed things out in Sam's favor. A 26-ounce container of Member's Mark whole cashews was $10.98 at Sam's, or 42 cents per ounce, while a 40-ounce Kirkland container was $18.99 at Costco, or 47 cents per ounce. Once again, Sam's came out ahead on a per-ounce basis.
What the head-to-head reveals
Looking across all 10 categories, a pattern emerges. The differences in any single item are often small, sometimes just a penny or two on prepared foods and beverages, but the savings widen on bulk staples like olive oil, ice cream, frozen broccoli, and canned goods. Those are exactly the items shoppers tend to buy in volume, which is where a few dollars per trip can quietly add up across a year of grocery runs.
It is also worth noting how often the comparison came down to size rather than sticker price. The dairy category looked like a Costco win at first glance, but the larger Sam's package made it a wash once you accounted for the extra ounces. The same per-ounce thinking flipped the snacks category to Sam's. For anyone serious about saving, the lesson is to compare unit prices, not just the number on the shelf tag.
Bottom line
After tallying every category, the clear winner was Sam's Club, which edged out Costco on most items and tied on the rest. That said, your own grocery list may include items that are cheaper elsewhere, so the best store for you depends on what you buy most. As a pro tip, check the warehouse club websites for seasonal specials and deals before you shop, since a single sale can flip the math on any given trip. Knowing where your staples cost less is one simple way to get the most out of your Sam's membership and keep more money in your pocket every month.
Editor's Note: Portions of this story were drafted with assistance from generative AI tools. All final creative decisions, edits, and fact checking were done by human writers and editors.
