Walmart must face a class action lawsuit that ruled that the retailer overcharged customers with "deceptive and unfair pricing practices."

Plaintiff Yoram Kahn alleged that the world's largest retailer "takes advantage of consumers in Illinois and nationwide with deceptive and unfair pricing practices."

Kahn argued that while the price discrepancies were small, they "add up to hundreds of millions of dollars each year."

"Kahn alleges that Walmart is aware of these discrepancies between shelf prices and register prices and that its unfair and deceptive pricing practices are pervasive and continuous," he said.

Kahn alleged that he shopped at a Walmart store in Niles, Illinois on August 2, 2022, and relied on the marked prices but was greeted with a significant markup when he checked out.

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"When Kahn checked out, the actual prices of these six items scanned at ten to fifteen percent markups above the shelf prices," the court ruled.

"In total, Kahn paid Walmart $1.89 in overcharges on these six items, nearly seven percent of the pretax total of his bill," they said. "Small change for Kahn as an individual, no doubt, but keep in mind the volume of Walmart’s business."

Reversing a lower court judge on Wednesday, the 7th U.S. Circuit Court of Appeals in Chicago ruled that consumers could try to prove that Walmart used a fraudulent "bait-and-switch" method that violated the state's consumer protection laws.

The plaintiff alleged that Walmart violated the Illinois Consumer Fraud and Deceptive Business Practices Act, the Illinois Uniform Deceptive Trade Practices Act and other states’ consumer protection statutes.

The court also disagreed with Walmart's argument that providing receipts after purchases negated any unfairness caused by inaccurate shelf prices.

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Walmart, based in Bentonville, Arkansas, did not immediately respond to Fox News Digital's request for comment.