I think we've all encountered such disappointments. You have my heart-felt sympathy.
I'm getting older. If I can walk or ride my bike to a store that charges just a little more than the one I must drive to -- I figure I'm saving money on gas, saving my time and sanity (I don't like sitting in traffic), and maybe helping the environment. So it's frugal in my mind to take distance traveled into account. But I must admit I am still sometimes suckered in by advertisements -- and too often they are switch and bait or limited availabilty, etc.