A store advertises an item in a circular at a certain price. When the customer buys the item and is about to pay for it, the owner says, "No, The price advertised is wrong. The real price is higher. We made a mistake in the circular, and you can see on the bottom of each circular in tiny letters it says, 'Not responsible for any errors'."
I know that in certain U.S. states, the disclaimer may or may not allow the store to do this. Halachically, must the owner honor the advertised (mistaken) price considering that the customer is about to purchase the item (i.e. - it was scanned, but cash was not yet tendered)? Or, can the owner rely on the fine print disclaimer (see assumptions, below) and he can charge the higher price?
The rules of "fine print" - Does this work in halacha? The majority of people don't read it, and most don't understand "legalease". Granted, in this case, the single sentence is understandable, but still, most people may not notice it. Thus, perhaps, this is "lifnei iver" - how clearly most something be stated to avoid misleading people?
Generality of the disclaimer - The disclaimer is placed on every ad. It therefore seems that this exempts the owner from randomly changing his mind on the price whenever he feels like it and using the ad as a backup. Seems like a form of "gneivat da'at" or something similar. The owner is trying to weasel his way out of his own error.
Who is responsible for the error? / Benefit of doubt - Maybe there really was a mistake! The owner sent the ad copy to the printer showing the correct (higher) price, but the printer printed it incorrectly. OTOH, is the owner responsible to place another sign near where the item is sold stating the correct price or listing that the published price is wrong?