For those who do not know< Most Device Plans have Data limitations that will 10 dollars or more for per GB over usage depending on your plan, so say you have Comcast, and you limit is 300gb then 10 month for an additional 50gb. and for some mobile plans are much sticker and limited to less usage. so you need to keep tack of you usage on a regular basis!
One thing that takes much or most of your data limit will be steaming Youitube and netflix videos!
One way to cut down of the video streaming usage is to always set the video quality to Low, or the lowest quality possible, ( not the auto setting they have by default !)
I have posted a Video on how to cut down on this with Netflix below, but there are manmy other ways to cut down on your mobile devise usage !
https://youtu.be/Ifv1lxWDsqk
Hope this helps cut down your cost!
Maxx