Shoppers at one of the nation’s largest grocery chains may be unknowingly paying more for groceries. An in-depth investigation by Consumer Reports and two news organizations found that customers were often charged higher prices at checkout than what was listed on store shelves.

The investigation found expired sale tags on more than 150 different grocery items that led to overcharges at the checkout counter, including from beef, salmon, coffee, juice, vegetables, cough medicine and dog food.

So it makes sense that when a good deal is advertised and groceries are on sale – that’s the time to buy, right? Well, a new investigation by Consumer Reports found that the grocery chain Kroger, which has a big Texas footprint, was advertising sale prices – but charging full price at checkout.