0W30 was some time ago regularly available at Auto Zone. 0W40 was regular at WM for 10yrs.If only Castrol 0w-30 or 0w-40 was found locally. I've never seen those two products in any Walmart in a 100 mile radius. Which is why I ended up getting the Mobil 1 Euro FS 0w-40 instead. WM not putting it on their shelves for some reason.
Now it is Amazon.
M1 0W40 is in that league.