Re: We have used 4GB of data when we bought and watched one movie!!
Is it normal to use that much data per movie?
once the rented or puchased movie has downloaded, will it use data again to watch it?
If you purchased the movie, you will download it to your device. If you download it again (to another device, for instance), you will use that much data again. If you rent the movie, you download it, so you will also use that amount of data.
In the case of purchase, if you only download it to one device, you can watch it as many times as you want on that same device and not use any additional data.
Three to four GB is about right for a 1080p movie of about 1 hour 45 minutes to 2 hours in length. Of course, the video can be compressed, which would consume less data. Also, some movies come with "additional features" - especially when you purchase a movie from iTunes, which means more data. So the actual amount of data used to download "a movie" can vary, based on situation and content.