WE have the Verizon hotspot and have used it all over the US. The only time there are additional charges is when I go over the usage (which I have done a couple of times). The additional "packet" of usage is $10 and they warn you when you are approaching 100% of your usage. I use a Wilson Sleek (walmart.com) and bought the window mount antenna for the RV. Works fine when stationary. I haven't tried it on the road. Wilson also makes a truckers antenna that attaches different ways. Wilson has great customer service if you call them and ask what you need.