Costco’s Store Brand Won on Milk, Sam’s Club’s Won on Coffee. Washingtonians, There’s a Catch
Warehouse clubs are supposed to save you money, so many customers stop comparing prices.
But a TV station in North Carolina priced store brands at Costco and Sam’s Club, and the results may interest Washingtonians who shop at either one.
Here’s what that price check found, and what it can’t tell you.
The Station’s Test
Costco’s Kirkland Signature went up against Sam’s Club’s Member’s Mark in a store-brand test from WRAL, a TV station in Raleigh, North Carolina.
WRAL’s 5 On Your Side team priced the items between February 18 and 24, 2026.
The station posted the results on February 25 and updated the page on February 27.
It isn’t Washington pricing.
The station priced nine household staples.
It kept the comparison to each club’s in-house store brands, with outside brands left out.
That put Kirkland Signature at Costco next to Member’s Mark at Sam’s Club.
BJ’s labels, Berkley Jensen and Wellsley Farms, were in the test too.
BJ’s came in lowest on chicken and beef, though this article sticks to the Costco and Sam’s Club columns.
If you shop at Costco, watch the Kirkland Signature column. You can see all nine rows on the station’s page.
Peanut Butter Prices
Costco’s Kirkland Signature peanut butter was $0.18 an ounce in the station’s table.
Sam’s Club’s Member’s Mark was $0.09 an ounce.
That’s about half the price for each ounce.
For a 16-ounce jar, the table’s math works out to roughly $2.88 at Costco and $1.44 at Sam’s Club.
Not so fast.
Check the label before you act on that gap.
What Costco’s Peanut Butter Row Compares
Costco’s peanut butter row carries an Organic tag. Sam’s Club’s row doesn’t.
The BJ’s row and the grocery store row carry the tag too. That leaves Sam’s Club as the only row without it.
So the nine-cent gap compares an organic Kirkland Signature product with basic peanut butter at Sam’s Club.
The table doesn’t list a non-organic Kirkland Signature jar, so no Costco row matches Sam’s Club’s on type.
Among the three rows tagged Organic, Costco’s was the lowest: $0.18 an ounce, against $0.19 at BJ’s and $0.26 at the grocery store.
Ground Coffee Prices
Costco’s Kirkland Signature ground coffee was $7.33 a pound in the station’s table.
Sam’s Club’s Member’s Mark was $6.79, which is 54 cents less for every pound.
Nothing in the table marks either coffee as organic, so this row is a cleaner comparison than the peanut butter row.
For scale, the grocery store column listed ground coffee at $12.30 a pound.
Both clubs sat far below that.
Buy three pounds and you’d pay about $21.99 at Costco and about $20.37 at Sam’s Club.
That’s a $1.62 difference.
Buy that much every month, and the yearly gap is $19.44.
Where Costco Came Out Ahead
Costco’s store brands came in lower than Sam’s Club’s on whole milk and beef in the station’s table.
Kirkland Signature whole milk was $2.43 a gallon, against $3.44 for Member’s Mark.
That’s about $1 less a gallon at Costco.
Beef was $5.79 a pound at Costco and $5.98 at Sam’s Club.
On chicken, olive oil, butter and rice, the two clubs landed within a penny of each other or tied.
Neither club swept it.
If milk and beef are what you buy at Costco, the same table gives you no reason to switch.
Psst! How much do you know about warehouse clubs? Take our quiz and see how many you can get right.
Quiz
Warehouse Club IQ
Answer nine questions on Costco, Sam’s Club, and the history behind them. We bet you can’t get them all right. Prove us wrong?
Costco’s Kirkland Signature label takes its name from what?
Where Both Clubs Operate
Costco had 629 warehouses in the United States and Puerto Rico at the end of its 2025 fiscal year, according to its annual report.
Sam's Club operates almost 600 locations across the U.S. and Puerto Rico.
If you live near both a Costco and a Sam's Club, you can price the two store brands side by side.
Check both.
Sam's Club in Washington
Costco's annual report lists its home office at 999 Lake Drive in Issaquah.
Costco began operations in 1983, in Seattle.
Seattle's KOMO News reported in January 2018 that the Sam's Club locations in Auburn, Renton and Seattle would stay open until January 26.
A Yahoo Finance report from April 2025 said Sam's Club's website listed no locations in Washington.
The company declined to comment on any plans to open a club in the state.
That's the catch.
Before you plan around any of these numbers, check Sam's Club's club finder for a location near you.
Washington's retail sales tax doesn't apply to sales of food and food ingredients, under the Revised Code of Washington, section 82.08.0293.
A jar of peanut butter or a bag of ground coffee should fall under that exemption.
So the price you read on the shelf is the price you'd pay.
What the Test Can't Tell You
If you shop at Costco, the station's findings could come in handy. But don't read the table as a ruling.
The station priced both clubs during the same seven days in February 2026, so the table is a snapshot.
One week isn't a trend.
Costco says in its annual report that Kirkland Signature products are generally priced lower than national brands.
That claim compares Kirkland Signature with national brands. The station's test compared one club's store brand with another's.
Nothing in the table speaks to taste, so you'd be shopping on price alone.
The table lists prices by the ounce, the pound or the gallon.
You'd have to do the size math for your jar or bag, since your register price depends on what you pick up.
9 Reasons Washingtonians Keep Driving Into Oregon and Never Go Back
A short trip across the Columbia River changes what Clark County drivers pay at the pump.
Cross the Columbia River into Oregon, and the savings don't stop at the pump.
9 Reasons Washingtonians Keep Driving Into Oregon and Never Go Back
6 Rain Habits That Give Away a Lifelong Washingtonian
Longtime residents turn on their headlights in the rain without a thought.
Their other rain habits show who grew up in Washington.
