What is the cheap version of silk called?

The cheap version of silk is most commonly called satin, specifically polyester satin, or faux silk, artificial silk, or silk-like fabric. There are several fabrics marketed as affordable silk alternatives. The most direct and cheapest is polyester satin or polyester charmeuse, which imitates silk's shine but is made from plastic. Another common name is art silk or artificial silk, which historically referred to rayon, also called viscose. Rayon was invented as the first artificial silk and has a similar drape and luster but is made from regenerated cellulose from wood pulp. Today you will also see fabrics labeled as vegan silk, silky satin, or milk silk, all of which are usually polyester. In the higher quality but still cheaper-than-silk category, there is cupro, also called Bemberg, which is made from cotton linter and feels very close to silk while being breathable, and acetate and lyocell or Tencel satins. If a product says satin but does not say silk, and costs much less than silk, it is almost always the cheap version of silk, meaning polyester satin.