Such a low price is either a promotion to get you in the shop so they can do other work on the car OR they use recycled oil and the cheapest filter possible. In any case, it is illegal to sell oil that does not meet the normal API and other ASTM tests. However, such cheap oils are only good for garden variety cars; BMWs, Volkswagens, Mercedes and others will need special oil and filters.
It’s OK for you Ford Taurus or Chevy cavalier.