Sorry sir but you are wrong.
I'll reiterate my limited econ 101 experience: we assume perfect information for markets to be perfectly efficient, so having the price across all offerings is a good thing. What you should decide is if the extra cost at the given store is worth the added benefits (customer service, locality, other factors). This is commonplace today, for example when choosing eco-friendly dry cleaning, products without lead etc. Obviously people choosing Walmart are making the choice that the added services are not worth the extra price. Not everyone has the same values (which determine price) as you.