I'm one to normally pick on the consumer for being clueless, but these discount stores sell so much garbage it isn't funny. Up here, they sell expired pop (yes, I know, pop isn't milk, but they get expired pop essentially for free and then have a nice markup), factory seconds labeled the same as the high end product, other products that were never meant for the North American market in the first place, and so forth.
Consumer awareness is still important. When you need to buy motor oil, know the specifications you require and know what to look for. When you buy toothpaste, be sure that the languages on the tubes are some combination of English, French, and Spanish. If you don't recognize the language, much less the brand, leave it on the shelf. If the Dr. Pepper has an expiry date of a year ago, don't buy it.
My late father used to love these discount stores. Now, he'd never buy a substandard motor oil. But, boy, he used to buy some shoddy garbage that would make a Chinese factory manager blush.