How Chinese retailers can offer Americans steep bargains on clothes and why that could change

As a substitute teacher in her mid-20s, Lindsey Puls was delighted to discover the fashion world of Shein more than 10 years ago, lured in by its super-low prices — with tops selling for a few dollars, dresses under $10, and free shipping on orders over $29. The company, which was founded in China and sells clothing manufactured there, is now the top fast fashion retailer in the U.S. The answer has much to do with a trade rule known as the de minimis exception, which allows parcels valued under $800 to enter the U.S. duty-free per person per day.