Richard Gere as Edward Lewis, a rich corporate raider and womanizer from New York. Julia Roberts as Vivian Ward, an assertive freelance hooker with a heart of gold on Hollywood Boulevard. Ralph Bellamy as James Morse, owner of a troubled shipbuilding company Edward plans to take over. This was Bellamy's final acting performance before his death in 1991. Jason Alexander as Phillip Stuckey, Edward's insensitive lawyer. Alexander is best known for the sitcom Seinfeld, in which a VHS copy of Pretty Woman appears in Seinfeld's apartment. Hector Elizondo as Barney Thompson, the dignified but soft-hearted hotel manager. Laura San Giacomo as Kit De Luca, Vivian's wisecracking friend and roommate, who has taught her the prostitution trade. Alex Hyde-White as David Morse, James Morse's grandson, who is being groomed to take over the company. Amy Yasbeck as Elizabeth Stuckey, Phillip's wife. Elinor Donahue as Bridget, a friend of Barney Thompson who works in a women's clothing store. John David Carson as Mark Roth, a businessman in Edward's office. Judith Baldwin as Susan, one of Edward's ex-girlfriends. Laurelle Brooks Mehus as the hotel's night desk clerk. James Patrick Stuart as the day bellhop. Dey Young as a snobbish saleswoman in a dress store. Larry Miller as Mr. Hollister, the manager of a clothing store where Vivian buys her new wardrobe. Patrick Richwood as Dennis, the hotel elevator operator. Hank Azaria as a detective. This was Azaria's first speaking role. Amzie Strickland as Matron Lynda Goodfriend as a Tourist.

Based on this passage, who played julia roberts roommate in pretty woman? Let's give stream of consciousness first:
The relevant information to answer the above question is: Laura San Giacomo as Kit De Luca, Vivian's wisecracking friend and roommate, who has taught her the prostitution trade.
So, the final answer is Laura San Giacomo.