Who is Stephanie from Valis and what is their importance?

Stephanie is an 18-year-old drug dealer. She lives and works in Horselover Fat's neighborhood in Santa Ana, CA. Stephanie plays an important role in preventing Fat's death. Stephanie lives for hashish, the drug she both uses and pushes on the streets. Marijuana and cocaine are also her drugs oof choice. Stephanie, however, refuses to sell hallucinogenics like LSD (acid).