How do I disable Visual Studio Code auto save

As @Alex Varghese mentioned in his answer you can do it in the settings. One addition is even if you turn off the auto save option in your user settings, that will not over write the option you have under Workspace settings, so you have to do the changes there as well.

You can also do this changes by going to the settings.json which usually resides at C:\Users\user\AppData\Roaming\Code\User.

"files.autoSave": "off"

To edit your Workspace settings, you need to edit the settings.json file which resides at the .vscode folder of your solution.

"files.autoSave": "off"

Go to File-> Preferences ->settings

choose your auto save option from commonly used settings