For my daughter's 9th birthday party, I booked a 2 hour recording session at a local recording studio for her and her friends (6 girls in all).  The cost was $75 for 2 hours, and the tech showed them all of the equiment and how it worked, and then played 2 karaoke tracks that the girls were recorded singing.  I had made their invitations out of cd cases purchased at the dollar store and I inserted customized invitation in the sleeves. When their session was done, they all got a cd of their songs, and they had the perfect case for it.