Walmart is weird. I recently bought a grease cartridge from Autozone through WM's site, with free shipping (did not have a WM+/whatever equivalent of Amzn Prime either, just part of the sale), cheaper than I could have bought it on Autozone's site (not even counting an additional shipping charge) or even pickup at the local Autozone B&M. It was nothing obscure either, just Lucas Red 'N Tacky.