Instacart shoppers might find themselves paying varying amounts for the same groceries—even if they reside in the same area. This phenomenon has come to light following a new investigation by Consumer Reports.

The investigation revealed that Instacart has been conducting AI-driven pricing experiments across several prominent grocery chains, leading to notable price discrepancies. In some instances, shoppers encountered prices up to 23% higher for identical products.

Consumer Reports discovered these experiments happening at stores like Costco, Kroger, Safeway, Sprouts, Albertsons, and Target. According to Derek Kravitz, a reporter with Consumer Reports, every participant in their nationwide study experienced these pricing tests. Hundreds of consumers were asked to purchase the same items from the same retailers simultaneously, yet none received the same pricing.

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These price variations were not minor. For example, at a Safeway in the Seattle vicinity, some shoppers spent approximately $114 on a basket of groceries, while others paid close to $124 for the same items. Based on Instacart’s estimates of a typical four-person household’s grocery expenses, Consumer Reports estimated that such price differences could result in some families spending around $1,200 more annually.

Instacart acknowledged the findings of Consumer Reports, clarifying that only 10 retailers utilize its pricing tools and that the majority of customers still encounter standard pricing. The company also emphasized that it does not use personal or demographic information to influence the prices shown to customers.

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Target told CR it has no business relationship with Instacart. Safeway, Costco, and Kroger did not respond to CR’s questions, while Sprouts declined to comment. Instacart has since said it stopped running pricing experiments for Target and Costco.

So what can consumers do? CR recommends shopping in person when possible and leaning on simple habits that can reliably save money, such as planning your list and buying in bulk.

States are beginning to respond to concerns about algorithmic pricing. In New York, any price set by an algorithm must now carry a clear disclaimer. Lawmakers in California, Colorado, and Pennsylvania are considering legislation that would ban “surveillance pricing” altogether for certain types of retailers.