Toggle Data Widget 5.0 requires root access, which is not something you can get around for data manipulation since KitKat, if I’m remembering correctly.
To enable in Tasker, simply open the Toggle Data Widget 5.0 application, choose to allow external access, and then you can edit actions via Tasker plugin controls.
If you’re not into using Tasker or Locale to modify it, you can simply add it as a widget somewhere on your home screen and turn off data to save juice when you need to.
Keep in mind turning of data means any sort of WiFi calling applications you’ve got will go south, and chances are Hangouts will likely malfunction or not deliver texts messages if you’ve got google integration or are using a Google Voice number.
Data Toggle Widget 5.0 is $0.99 until November 26, 2014, at which point it will go up to about $2. The author has extended a three day refund period as well.
Download: Google Play