I've been using MetroByte By Tmobile (formerly Metropcs). It seems to be cheapest at $60/month. It works through my phone with no added doo-dads. I have an advantage in line of sight to a cell tower about 12 miles away. Signal was intermittent but a $150 Amazboost booster antenna took care of that. So here we are off grid and we're chatterboxing away on the largest grid in history.