Guitar Hero World Tour

As you play through all the instruments and their Careers you will come across Musicians that can later be unlocked once beating them in a battle or performing with them. Once they are unlocked you can purchase them from the Rocker select screen, Ozzy Osbourne costs $10,000 to purchase. You will be able to purchase him after you complete the fourth gig (Germany) in the Vocals Career on any difficulty. Simply play any song as him in either Career or Quickplay.

-It is possible to play with Ozzy Osbourne online before you purchase him, you must have him unlocked before you can select him though. To change your musician online select Preferences then Rocker.