Until the day her mother sent her out with enough S&H Green Stamps to buy a Bible, Sandra Cisneros' family had never owned a book. And though she checked out eight library books a week while growing up in the Chicago barrio, she never read about girls like herself Mexican-Americans. Even as a graduate student at the University of Iowa's Writers' Workshop, Cisneros says she was just ''hobbling around disguised as everybody else.'' But when she returned to the barrio in 1979 to teach reading, she started writing about what had most shamed her poverty in the cadences of the voices around her. This week Vintage brings out a paperback of her first book of stories, 1985's critically acclaimed The House on Mango Street, and Random House publishes Woman Hollering Creek and Other Stories in hardcover. ''My work is a Noah's Ark of sorts,'' Cisneros, 36, says. ''I've been very obsessed with getting everybody's voice on board.''