Generally, Tupperware is sold in specialty stores;

If it is out of town, the first factor to judge is the price. The lowest price for a Tupperware plastic cup seems to be 19 yuan) (this price is from a specialty store). If it is 1-4 yuan lower than this price, it is possible, but it is much lower, and it may be a fake. The second judging factor is quality and taste. Tupperware cups are of very good quality and have almost no plastic smell. You can put water in them and smell them. They are durable and will not break easily. Another thing is the cup lid. If it is tightened and the threads on the cup lid are opened, the 80% plastic in those places can be said to be genuine if there is no sanding with some fine powder or other damage.