If you’ve decided to upgrade your FL Studio version and finally have the official Pitcher, here’s how to get that pro sound:
This is widely considered the best free pitch corrector. It has a "Correction" module that provides that classic auto-tune sound with a very smooth interface.
MeldaProduction offers a free version of their MPitch plugin, which is a simple pitch correction and manipulation tool. You can download it from their website:
Voxengo Pitcher is a free VST plugin that offers basic pitch correction and manipulation features. You can download it from the Voxengo website: