My problems with Verizon have not been solved, but after experimenting, I have been using the following techniques to keep my data under 20 Gigs per month.
1) I downloaded the Facebook application and use it almost entirely on my cell phone. I can browse and post photos for a long time and hardly use any bandwidth that way. I also check this forum using my phone as often as I can.
2) I use public WiFi in campgrounds where it is free using the WiFi booster I bought. It does not increase the poor speed in commercial campgrounds that provide free internet, but it does really help find and keep a signal.
3) I use my iPhone 5 as a tethered hotspot when I can't get free WiFi. (I found that using it wireless is really slow and might allow someone to use my signal.) Tethering the phone to my computer and setting it as tethered only means no one else but me can use it so good security, and the speed is much better. As long as I have 2 or 3 bars of 4 LTE service, I get fairly fast and reliable internet this way and it uses maybe 1/5 as much bandwidth as does my jetpack. Even uploading photos is fast this way. The problem with the phone is that it does not work very well with only 3G service.
4) When I have very poor cell service, I use my jetpack. There are also times I have to use the jetpack to view student presentations live. It uses a lot of bandwidth, but other solutions just don't give me a good enough signal.
I am still going to track the times I use the new jetpack and possibly add my old jetpack to my "family" plan for $20 a month. I swear it did not use as much bandwidth. This assumes I can get it fixed.
Another thing that came up is that I agreed to teach a third class in the fall. This means I will be working what is basically a 3/4 time job, so I may end up going up to 30 Gig, which is absurd, but I want to keep my job because the money is nice so I need reliable service. I will still be using techniques 1-3 to conserve bandwidth.