For serious study, (available via AbeBooks or Alibris) or request it through interlibrary loan. For casual exploration, begin with the Chinese Text Project’s bilingual version and supplement with Feifel’s public domain articles (available on JSTOR with free registration).
For those who locate a PDF of the Baopuzi , specifically the Inner Chapters, a word of caution is necessary. The text is notoriously difficult to translate because it employs "oblique language" or code words. baopuzi english translation pdf
The Baopuzi suffers from what librarians call the "20th-century black hole." Ware’s 1966 translation is still under copyright (life of author + 70 years in most jurisdictions). Pregadio’s 2011 work is actively sold. The only public domain translations (Feifel, 1946) cover less than 15% of the text. For serious study, (available via AbeBooks or Alibris)