A number of translations of Nietzsche's Genealogy are available for free online, These will typically be older translations, long since passed into the public domain, which is why they are free.

• Friedrich Nietzsche, On The Genealogy of Morals Kaufmann translation (Internet Archive)
  
  
• Friedrich Nietzsche, On The Genealogy of Morals Samuel translation (Project Gutenberg)
  
  
• Friedrich Nietzsche, On The Genealogy of Morals Samuel translation (Wikisource)
  
  
• Friedrich Nietzsche, On The Genealogy of Morals Johnston translation (Johnstoniatexts)
  
  
• Friedrich Nietzsche, On The Genealogy of Morals Diethe translation (Cambridge, available through U of Santa Cruz)

You can find a free audio version of the text at Librivox

• Friedrich Nietzsche, On The Genealogy of Morals Samuel translation (Librivox)

You can find the German original of the text as well at Nietzsche Source

• Zur Genealogie der Moral. Eine Streitschrift (Nietzsche Source)