Hello there! I am a professional audio engineer and music producer. Also, I've been a singer for over twelve years. Depending on the budget you've got for the project, I can give you and advice of what you can purchase, specially in hardware. If you're willing to buy a live autotune, today is your lucky day because Waves Tune Real-Time Plugin is on sale today for $29.99 USD. This sale ends in 20 hours.
Contact me, so I can guide you on what else you should get for the audio system.
Looking forward to hearing from you soon.