Pretty sure 120 MB/week is atypical for tech nerds. I have the T-Mobile $30/mo plan and reach the cap every other month, and have to renew early to get LTE speeds. And I'm on WiFi at home and work.
Perhaps it is atypical, though I spend a lot of time on my phone and don't go through more than 1 GB/month because almost all of my browsing involves text and images, with videos usually only while I am indoors (generally over WiFi).