I go anywhere between 700MB to 20GB a month depending on some things. I could average 10GB but when I notice it approaching that I try to stop using data. On average...I would say 5GB to 10GB. Netflix, web browsing, youtube, Tune in radio app, hotspot when over my kids mother house. She has no cable and I gave her a wifi blu ray player.
Just saw one time I hit 33GB...wow...those big amounts are rare. I dont got over her house that much. And I got wifi at home.