I have always used my phone mobile hot spot to my laptop. I was on limited data and as it ran out they would text type YES if you would like to increase your data by 2G for $10 more or you will be charged$15.
So we never watched videos and while out in the boonies I would go up to about 20 or something and a couple hundred bucks. Recently I went with the unlimited and it was slow slow slow so I called them and they said it's because so many people are on it in my particular area.
Although I'm in a larger city the map shows poor coverage. On their recommendation I went to "beyond" unlimited and it's been pretty good. Not perfect but usually works. Videos stall sometimes but not terrible. I don't know how much data I have used but the bill was $208 for two smart phones.
I probably won't turn on the internet when I get home so that saves minimum on time of 6 months x $35 per month.