MATERIAL FANS: Mark Smith of Anaheim is...

MATERIAL FANS: Mark Smith of Anaheim is 20, unemployed, and never, ever , spends 50 bucks to buy a book. So why was he willing to spend that much to buy Madonna’s new “Sex,” an instant hit in Orange County bookstores Wednesday? (D1) “I don’t know; I’ve got all her albums,” Smith says. “I guess I just wanted it.” . . . He lucked into 25% off at Waldenbooks in the Brea Mall. Most local bookstores say its demand has already produced long waiting lists.