I recently discovered the above, and after paying attention there are many items that are less expensive at WF. The whole fresh fruits and vegetables are the same price or cheaper than other local chains, and are also very high quality. The only place that beats them on price is Walmart, but quality is hit and miss (normally miss).
I have found beer and wine to be $1-$2 cheaper at WF than local chains. Not everything of course, but I tend to keep the same wine and beer around the house so I notice pricing. Good cheese can also be had for less money at WF. The WF brand whole bean coffee is also cheaper than anything else I have found locally.
If frugality is the goal I have found that for most packaged stuff Walmart is the way to go. Then WF for fruits and veggies, and finally Harris Teeter (local chain in the south) for meats (never ending special boneless/skinless chicken breasts are always $1.99/lb).