LA Times on peso

Being in a region for 2,3,4 months isn't living there
I don't have time to search for everything from local merchants other than fresh fruit and vegetables
So non residents will see a rise in costs from the depressed peso, so will residents, we see many Mexicans at Commercial so costs for residents will also increase
As Rob said he doesn't need to shop tante big corporations but he has the local knowledge and the time

If you are here for months then I can only say you are missing half the fun of being in Mexico!

Getting back behind the mercado searching for something is IMHO way more fun than a few hours drinking beer on the beach. I often get locals joining me in my search, taking me from store to store, gathering ideas where my "thing" might be. And if we can't find "it" we will probably find someone who can make it.