To get autotune on Audacity, you will need to have the 1.3.10 beta version from Audacity's website. Verify that you have autotune or G-snap in the plug-ins. You may need to download G-snap from the internet. First, open up Audacity. Then, go to edit and select preferences. Go to effects and click rescan BST effects next time Audacity is started. Then, click the okay button. Close out of Audacity and then reopen it. The program will then import your new files. Your new files will then show up in your effects menu in Audacity for you to utilize.