Costco May Cost Oregonians More Per Ounce Than WinCo or Walmart, Tracker Suggests
Big packs. Big cart.
Big savings, right?
A Portland price tracker suggests that may not always be true for Oregonians.
Here’s what it found, and how to test your own cart.
Portland’s Price Tracker
Stumptown Savings is a Portland grocery newsletter. It checks Costco and other stores every month.
Founder Bryan Vance told Willamette Week in a March 2026 Q&A about it.
He tracks the same 20 items at 20 stores across Portland. The paper’s headline calls it a past year of tracking.
The July report, published August 11, 2026, has nearly 4,720 individual prices so far.
The August 2026 report explains the method.
It prices a fixed basket of 20 common grocery items at Portland-area stores.
It does this one day a month, typically in the third week.
Every figure below is Vance’s account of his data. It is not an independent calculation by the paper.
If you shop elsewhere in Oregon, your stores may not appear in that data.
How Costco Stacks Up
Costco isn’t the cheapest store in town once you compare per ounce, Vance said in that March 2026 Q&A.
That is the past-year result, not a fresh calculation. WinCo and Walmart beat it.
Per ounce means the price of a package divided by the ounces inside.
That puts a small pack and a big pack on equal footing.
So the total on your Costco receipt says little until you know how many ounces it bought.
To test it yourself, pick three items you buy often and read the Costco unit price for each.
Then read the unit price for the same items at WinCo or Walmart, in the same unit.
If the Costco figure is lower, Costco wins for that item.
What Oregon’s Unit-Price Rule Covers
Before you compare a Costco tag with a WinCo tag, find the unit price next to the total.
Oregon law says larger chain grocery stores must show it on packaged food and household cleaning products.
A unit price is the price for a single whole unit of weight, volume, measure or count.
Fresh fruits and vegetables are exempt. Temporary sale prices are exempt too, unless they last more than 30 business days in a row.
The Oregon Department of Agriculture picks which unit each product uses. So make sure two tags use the same unit before you compare them.
WinCo’s Price Lead
In the same Q&A, Vance called WinCo the cheapest store in town.
He went further: WinCo is the cheapest store for 99% of the stuff you can buy there.
That is an estimate for the whole store, since the tracker itself prices 20 items.
WinCo doesn’t advertise and doesn’t accept credit cards, and skipping cards saves it 3%.
The tracker’s July report still calls WinCo the cheapest store in the tracker by a wide margin.
For grains and similar staples, try WinCo’s bulk bins.
If Costco is your default, WinCo’s tags are the first tags to compare.
Grocery Outlet and Walmart
By Vance’s account, Costco also trails Grocery Outlet in many months. There’s a different reason to go there.
Grocery Outlet is probably where you’ll see the highest markdowns.
The sales aren’t the same in every store, so check your store first.
The September 8 report is next. Costco’s basket total barely moved, down 0.1% from July.
Walmart’s jumped 9.7%, its highest average since the tracker started.
Picture a $100 Walmart basket in July. At that jump, it would cost about $109.70.
That report also listed Costco, WinCo, Walmart and Grocery Outlet as Budget Champions.
Walmart is the other store that beats Costco per ounce.
Stumptown Savings says Grocery Outlet’s basket moves with whatever was on the shelf that week.
In the July data, that basket dropped 22.5%, the largest single-store swing that month.
Those are basket totals, not per-ounce prices.
But they show why rankings shift from month to month, and why one trip proves little.
Psst! Are you getting the lowest price on your groceries? Run through this checklist and see where you stand.
When Bulk Buying Pays
Costco can save you money if you can afford to buy in bulk, Vance said.
It’s also a good place for organic meat, which you can buy in bulk at a decent price.
A big pack only saves money if you use it.
If half of it spoils, the price per ounce you paid covers ounces you threw away.
So freezing or sharing what you can’t finish helps the savings hold up.
In its fiscal 2025 annual report, Costco says its Kirkland Signature products are generally cheaper than national brands.
The August 2026 report lists Costco as the lowest price in Portland for whole milk, ground coffee and vegetable oil. It marks each one as sold in a larger quantity.
When a Costco total looks low, check the ounces in the bigger pack before you call it the lowest price.
8 Things WinCo’s Employee Ownership Changes for Oregonians
WinCo is employee-owned.
Does the way the company is owned change anything about a normal grocery run?
