For more than one year, Walgreens has “consistently and systematically displayed inaccurate sales tags, overcharged customers, failed to remove expired sales tags, failed to consistently ensure the price charged is the same as the price advertised, and used misleading or confusing in-store signs” in violation of state law, according to a new complaint filed by Missouri Attorney General Chris Koster.

The suit follows an investigation that included undercover visits by members of the AG’s office to eight Walgreens stores in five cities across the state in June and July. The suit alleges that nearly every store visited had pricing discrepancies where the checkout cost was higher than the displayed or advertised price. On a single day in July 2013, “overcharges and inaccurate advertisements were documented in every store inspected,” the AG alleged, with overcharges ranging from a few cents to more than $15.00 per item. Of a total of 205 purchased products, investigators found 43 price discrepancies – nearly 21 percent of the purchases.

The suit also claimed that Walgreens’ shelf tags are confusing. “The numerous price tags displayed and the format of the tags containing multiple prices, discounts, or points require consumers to review tags for an unreasonably long period of time, and are likely to cause confusion to a reasonable consumer as to the actual price of the item being offered,” the suit contends.

According to the complaint, Walgreens further lures consumers to buy with a rewards program promising additional price reductions and savings. But rewards members do not receive all the membership savings as advertised, Koster said, and some shelf tags include fine print indicating that reward members need a coupon in addition to their membership to receive additional savings.

The complaint alleges that these unfair and deceptive practices violated Missouri state law and seeks injunctive relief, the costs of the investigation and prosecution of the action, as well as a civil penalty.

To read the complaint in Missouri v. Walgreens, click here.

Why it matters: “Consumers have a right to expect the price they will pay at the register is the same as the price displayed on the shelf,” Koster said in a statement about the case. “The sheer volume of tags on the shelves makes it nearly impossible to recall the details of each offer. Consumers should not have to double-check the price tags or signage and compare them to the prices charged at the register.” The AG also encouraged consumers who observed or incurred any deceptive pricing at Walgreens – or other retailers – to contact his office.