Its surprising to me how cheap Walmart is for their most barebones oil change. About $30 OTD for the bottom of the barrel. That's their "pit crew" oil change. Suspect you get a fill of **** oil and a filter, but that's certainly better than nothing. No clue what they use.
Occasionally at random nasty super shady gas stations, the kind of places that sell "water pipes" K2 and Kratom, I'll look over the bottles of oil. Always no name random stuff with questionable labels. But when 90% of the cars pull up without license plates, mufflers, and scream like a siren from power steering pumps, I don't suspect the owners are too interested in preventative maintenance.