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With grocery prices still stretching household budgets, many shoppers assume that Walmart is the cheapest place to buy food. But a new analysis suggests that isn’t always the case, especially in Southern California.

According to a recent study commissioned by Consumer Reports, the lowest grocery prices in Southern California were actually found at Costco, beating Walmart by a significant margin.

The findings highlight how much shoppers can save simply by choosing the right store.

costco produce aisle — Image Credit: Deposit Photos

Costco Came Out as the Cheapest

Researchers compared grocery prices across major supermarket chains in Southern California, using Walmart as the baseline.

The results showed that some stores were noticeably cheaper than Walmart, while others were far more expensive.

The three most affordable options in the region were:

Costco — about 20% cheaper than Walmart
WinCo Foods — about 4.3% cheaper
Aldi — about 4% cheaper

Warehouse retailer Costco stood out as the clear winner. Its bulk-pricing model allowed shoppers to spend significantly less on the same grocery basket than at Walmart.

For many families, that difference can add up quickly.

Some Grocery Chains Cost Much More

The study also revealed that several well-known grocery stores charge noticeably higher prices for the same items.

Compared with Walmart, the following chains were more expensive in Southern California:

Target — about 8.2% higher
Food 4 Less — about 10.3% higher
Stater Bros. Markets — about 15.6% higher
Trader Joe’s — about 18% higher
Ralphs — about 21.9% higher
Albertsons — roughly 26% higher
Vons — roughly 26% higher
Whole Foods Market — about 35% higher

Whole Foods ranked as the most expensive grocery option in the study.

How the Study Compared Prices

The price comparison was conducted by the retail research firm Strategic Resource Group on behalf of Consumer Reports.

Researchers visited stores in person and recorded shelf prices over a 48-hour period in each metro area. The grocery baskets included a mix of packaged goods, fresh produce, and meat.

Sale prices and loyalty-card discounts were included in the totals, but manufacturer coupons and app-only deals were excluded.

Because mainstream grocery chains often carry the same national brands, researchers could compare many of the exact same items across different stores. Specialty stores and private-label focused retailers had fewer overlapping products, resulting in smaller comparison baskets.

The Real Impact on Your Grocery Budget

These price differences can translate into major savings over time.

For example, a $200 grocery trip at Walmart could cost about $160 at Costco based on the study’s pricing. The same basket might climb to around $270 at Whole Foods.

Over the course of a month, that gap could mean hundreds of dollars in extra spending.

For households in Southern California—where housing and everyday living costs are already high—simply choosing a cheaper grocery chain could make a noticeable difference in the monthly budget.

Why Some Stores Cost More

After the report was published, Whole Foods responded by noting that price comparisons don’t always capture factors that matter to some shoppers, such as ingredient standards and sourcing practices.

The company also said it has reduced prices on about 25% of items over the past 18 months, particularly its private-label products, while maintaining quality standards. Members of Amazon Prime also receive additional in-store discounts.

Still, the study reinforces one clear takeaway: where you shop can matter almost as much as what you buy.