Costco vs Amazon vs Walmart,
per unit
Enter a Costco item number or product name. See what the same item costs on Amazon and Walmart, per ounce or per unit, and which store is cheapest.
Costco vs Amazon and Walmart prices, compared fairly
Comparing Costco with Amazon or Walmart by sticker price is misleading. Costco sells 8-packs, 2-liter bottles and 100-count boxes, while the other stores list smaller packs, multi-packs from resellers and different sizes of the same product. The question that matters is the price per ounce or per unit.
This tool does that in one step. It looks up the Costco item, searches Amazon and Walmart for the same product, picks the closest listing on each store, reads the pack size from every title and ranks the three stores per unit. When the titles don't state comparable sizes, it says so instead of guessing. Resellers use it to spot arbitrage gaps, brands to check their price position across the three retailers, and shoppers to see whether the membership pays off on an item.
It runs on the Scavio Costco API with the Amazon API and Walmart API: Costco product or Costco search, then Amazon and Walmart search. You get 5 free comparisons a day, no account. To check a whole sourcing list, get an API key and run it daily through the API.
Want warehouse shelf prices instead of costco.com? Use the Costco price checker. Comparing just Amazon and Walmart? Use the Amazon vs Walmart price comparison.
How to compare Costco, Amazon and Walmart prices
- 1
Enter the Costco item
Type the Costco item number from the shelf tag, receipt or costco.com, or type a product name and the tool uses the top costco.com match.
- 2
Let it search Amazon and Walmart
The tool reads the Costco title, searches Amazon and Walmart for the same product, and picks the closest listing on each store by title, brand and pack size.
- 3
Compare per unit
Read the three prices side by side. When the titles state a pack size or count, prices are normalized to price per ounce, per fluid ounce or per unit, and the cheapest store is called out.
Frequently asked questions
Is Costco cheaper than Amazon and Walmart?+
Often, once you compare per unit. On October 20, 2026, Costco's Tide Pods with Ultra Oxi 100-count was $29.99 on costco.com, about $0.30 a pod. The closest Amazon and Walmart listings were 104-count packs at $35.97 and $36.97, about $0.35 a pod. It is not always true, so the tool checks each item instead of assuming.
Why compare per unit instead of the sticker price?+
Costco sells bulk packs, so its sticker price is usually higher than a smaller pack elsewhere even when it is cheaper per ounce. The tool reads the pack size and count from each title (for example 8 x 7 oz, 2 L or 100-count), converts them to a common unit, and ranks the stores on price per ounce, per fluid ounce or per unit.
What happens when pack sizes can't be compared?+
The tool says so. If a title has no size or count, or the sizes are not comparable, it falls back to sticker prices and labels the result as not normalized so you check the pack sizes yourself. A match that is more than 4x off per unit is flagged and left out of the ranking, because that almost always means the title states the wrong size.
How does it find the same product on Amazon and Walmart?+
It searches both stores with the brand, product name and size from the Costco title, then scores every priced listing by title overlap. Listings that do not name the brand lose points and listings with the same pack size gain points. The best one on each store is labelled as the compared match, and the next candidates are listed so you can check them.
Why are Kirkland Signature items more expensive on Amazon and Walmart?+
Kirkland Signature is Costco's own brand, so on Amazon and Walmart it is usually listed by third-party sellers who mark it up. On October 20, 2026, Kirkland Signature Organic Extra Virgin Olive Oil 2 L (item 692731) was $20.99 on costco.com and $31.49 from a third-party seller on Walmart, 50% more per fluid ounce. The seller name is shown on each Walmart listing.
Is this useful for online arbitrage?+
It is a fast first check for retail arbitrage from Costco: is there a gap on Amazon or Walmart worth a closer look? For a real buy decision you also need fees, shipping, sales rank and listing restrictions. The API lets you run the same three lookups across your whole sourcing list and add those checks in your own code.
Which Costco price does it use?+
The costco.com online price. Warehouse shelf prices are set per warehouse and are often lower. To see the shelf price at the warehouses near a ZIP code, use the Costco price checker, which prices one item at the 9 nearest warehouses.
What can I type into the box?+
A Costco item number (like 1492456), a costco.com product link, or a product name. For a name, the tool compares the top costco.com match and lists the other matches so you can pick a different item. It covers costco.com, amazon.com and walmart.com in US dollars.
Is it free?+
Yes. You get 5 free comparisons a day with no account. To keep going, get an API key: 50 free credits on signup, no card required. One comparison like this costs 3 credits through the API.
Can I run this from my own code?+
Yes. POST /api/v1/costco/product with an item_id (or /api/v1/costco/search with a query) returns the Costco title and price, then POST /api/v1/amazon/search and /api/v1/walmart/search with the cleaned title return every listing with price, rating and seller. 1 credit each. The full JSON is available via the API, so run it daily through the API to track the gap over time.
Compare your whole sourcing list with the API
This tool is three calls on the Scavio API. Run every Costco item you track against Amazon and Walmart from your own code, spreadsheet or agent, and keep the full JSON.