On my phone i have the entire worlds map set saved offline, and enough music to not repeat over 4 weeks, so i barely rely on the internet beyond work, (I'm stingy that way),
I'm tied into the works data pool of 47GB and rarely go over 2GB, mainly because i disabled all the crap that came with my phone, and never try using social media, websites like EEVblog really use nothing but a drop in the pond even after many hours, or if i'm reading news sites i use the adblock browser to make sure i'm not loading all there crap,
Equally in most browsers you can set it to not autoplay videos which helped me the most,
Closest offer i know to unlimited was a plan offered in London main airport, 30 pounds for 30 days unlimited roaming data, and i know they meant unlimited as one of the people that went with me got it and tallied 114GB by the 29th day, biggest PITA was come the last day, you could only recharge it in the UK.... so he was cut off half way to navigating to our second last hotel, in a rental car somewhere in the middle of Greece, (Now you see why the world map set)