Kamikaze
TAL Vocoder is free. Otherwise I'd look at paying for Image line Vocodex, or Melda MVocoder.
try the demos before paying, in case it's too demanding for your system.
https://tal-software.com/products/tal-vocoder
JRR Shop and Audio Delux are worth checking for the Vocodex, and seeing the price 'in the cart'
+1 on the TAL Vocoder. Definitely worth a shot, and the TAL freebies generally sound good.
Has some cool robot voice presets, and fun to play with.
To get it going, you just need to insert the Vocoder as an audio FX in an audio track. You can either feed a live audio input to this track, or use an audio clip. The Vocoder will modulate this audio track when you play your controller.
Then insert a MIDI track using your controller as input and route that MIDI output to the Vocoder.
Good times!