A T-shirt decorated with the words "Crack Whore" costs $16.95 on the Internet. Browse photos of Maggie's life Maggie Williams considers this, her head tilted like a confused terrier. "Who would buy that?" she asks in a raspy voice. "That's the stupidest thing I ever heard." Maggie states this with authority. She has spent nearly half her 52 years selling sex acts to earn cash for crack, five bucks at a time. Her entire universe is a six-block rectangle in Riviera Beach, west of the old Spanish Courts Motor Lodge, where drug dealers seem as common as vendors at a...