General average for standard definition movie - with decent compression - figure on 1GB per movie. When I download movies and tv shows it can be anywhere from 20-50GB for a couple dozen (I usually save up and download on another sim using time so it doesn't go against my monthly data limit). If I stream Netflix and youtube throughout the day and my wife streams music and youtube and on facebook, we have used 2-3 GB in a day. We currently use 100GB+ a month.