Option 1: Check out how much you’re using right now! Log into your current account and look for the section on your monthly data usage.
Option 2: You can go to your phone’s settings (Settings > Cellular Data for iPhone, or for Android Settings Menu > Data Usage > Select Dates for Android). Do a little hunting around and see what you use.
Option 3: We got you. For a rough idea of how much data you need to check out our handy blog.