You're usually fairly safe if you pay the 'going rate' for a product. Check several listings. The ones listed as 1.00 yuan are asking you to negotiate which is more effort than you probably want to deal with, the ones 15-30% under are probably from a rejected batch or a line of functional fakes, the real bargain prices are probably not even what you think you're ordering, etc.

You'll still get burned sometimes. But the savings!

Why wouldn't a seller offer a crap product for full price? What does it cost them to offer you a reject at full price?

Well, that's where the second thing to look at comes in; how many sales the individual listing has. If more than a half-dozen people have bought it and it's still up, it's costly for the vendor to take the listing down and replace it when a 1-star rating is left.

Sometimes you gotta roll the dice, but yeah that is very risky with things like integrated circuits, or really anything more complex than discrete components.