Yes, but to put one price on the price tags and then sell it for a different price at the register can be perceived as false advertising/misleading customers. If an item is incorrectly priced, then the store does not have to sell it at the incorrectly advertised price, because as you said, it's an invitation to treat. However they also cannot proceed and sell the item at a price that was not the advertised price. The retailer legally has two options if an item is incorrectly priced:
1: agree to sell the item to the customer at the incorrectly advertised price, or...
2: withdraw the item from sale, then reprice the item correctly and make it available for sale at the corrected price (i.e. re-shelve it with a new price sticker)
I experienced this a few years back when I went to TRU and found a Darth Vader/Death Star Transformer sitting on a shelf with a price tag that said, "Star Wars Transformers $30". I took the toy to the register, and it scanned at $100, but I told the cashier about the price tag. She then had it checked, and sure enough it was advertised on shelf for $30. At this point TRU had only two choices - and they chose to sell it to me at the advertised price, which I didn't complain aboutThey would have been equally entitled to withdraw the toy from sale, which I wouldn't have complained about either.