I got hit by this AT&T usage cap for internet downloads. I went through 250GB of downloads in less than a month. Most of it was internet backups of a newly installed system. They don't offer a data tier without a cap in my area so I was stuck paying $10/10GB over that month. Next month I added a $30 unlimited data charge to my bill. That's OK as I'm consistently going over their cap again due to backups. Unless I buy much more expensive plan from a commercial provider and pay for Fibre installation, I'm stuck.