I can't recall the exact prices as it was a few years ago , but I saw an ad in HF flyer for an air compressor on sale , I head to the store to get one , I get there and they didn't have any in stock , but they did have one that was bigger and a bit more $$$. Not wanting to waste the trip and needing a compressor , I called someone over to get me one from the back.
Guy tells me something is wrong , that compressor should be $749 and not $499 , seems someone screwed up. He calls the manager over and the manager says " our mistake , if you want it at that price I will honor it today , I am having that price fixed. ( it was an in store manager sale ). I then asked if I could use my 20% off coupon.....his reply " yer killing me here kid , but yes you can ".
I did buy the extended warranty to make up for it.
The only other time was when I was buying a car , I had went to the lot and looked at this car ( used ) 3 times that week , figured I would think on it over the weekend and go back Monday and decide. Sunday paper comes out , dealer has what looks like the same car I was interested in marked down $3000 !! I go in Monday , tell the salesman I will take it , he starts to run the #'s and tells me " good deal , that is on sale to for $4999 , good thing you waited. "... I then said , " no its on sale for $3499 ".
He double checks , then realizes what happened. Somehow the advertising dept doubled the $1500 this group of 20 cars was to be reduced. He said " If you have the ad we will honor it , otherwise we are reprinting a retraction and corrected prices ".
Unzip jacket pocket , pull out ad

* only reason I brought it was to verify the stock # was the same as the one I was looking at early. Car purchased for advertised price.
In neither case , did I feel they "owed" me anything , or HAD to honor their price. Had either said " No , sorry , that price was a mistake " , that is where I would have left it.
People make honest mistakes , I don't feel I need to make them pay for them.
But I wouldn't say there was anything immoral about holding them to it either...comes down to personal opinion.