Clark’s newsletter says:”If you’re a Costco or Sam’s Club member, you’ll likely find the best deals on car batteries at your favorite warehouse store.” That isn’t my experience. I purchase my car batteries from my car dealer’s parts department. I was shocked when I found this our but it is true. I have Toyotas, a Honda and a Ford (motorhome chassis). In each case the batteries have been 15%-20% cheaper and they come with 5-7 year warranties (typically 3 year full replacement then prorated). I do have to bring my old battery core for exchange and install the new battery.
You can get quality batteries at about any auto parts store. My Chevy Volt needed a new 12v AGM battery. My local CarQuest (now owned by Advance Auto) has the DieHard brand and they had an exact replacement. Remember Sears? They used to sell tons of Diehards. Apparently Advance bought the DieHard brand.
Napa has quality batteries but in my area Napa prices seem higher than the other parts stores. Autozone and Wal-Mart? I’ve heard some complaints about those, but I have a large Marine deep cycle from Wally-World (Everstart). It is a few years old so I think they are ok.