: The most popular free choice for Audacity. It is lightweight and perfect for the classic hard-tune sound. It also allows you to control pitch via MIDI input, meaning you can "play" the correct notes on a keyboard to guide the vocals.

If you are on Windows, Audacity can sometimes crash when loading heavy VSTs. The stability of Autotune plugins in Audacity is hit-or-miss.

(Points added for being free and accessible; points deducted for a destructive workflow that discourages experimentation.)