A feature-length HD motion picture will consume 1.5 - 2 GB of data streaming at the best resolution from NetFlix or Amazon Prime Video. (As a retired IT person, I don't understand how anyone can use 40 GB in a month with just email and web surfing, though...)
Verizon has just come out (last week) with some newly-structured prepaid plans that includes one with unlimited data (truly unlimited - not throttled past a certain point) for MiFi hot-spots. We just switched our MiFi and and two phones over from a post-paid plan, got unlimited data on the MiFi (3GB/month on each phone which is MORE than enough for us) and cut our monthly bill in half. We use an Amazon Fire Stick TV device and are now streaming from the above sources plus YouTube, etc., without worrying about data usage.
Rob