I looked at netbuddy and could not order as all their stuff seems to be out of stock and stays that way. They have never responded to info requests. More research found
http://www.otrmobile.com. There is an initial cost for sim card and setup of $100 to use your own device or you can buy device with sim card directly from them. Then it is $60 / month for unlimited data, no throttling and no contract. They use the AT&T network.
As I already have a wifi ranger setup, I purchased Netgear 4G LTE Modem from Amazon for $109 (
https://smile.amazon.com/gp/product/...?ie=UTF8&psc=1), installed the OTR sim card and connected it to the wifi Ranger. Just took a trip with the teenage grand kids so phone use was non stop as well as the netflix viewing and I must say I am impressed with the speed provided, Mostly 50-60 mbps down and 30-40 up. Never noticed any slow down due to throttling.
The wifi Ranger is powered from RV 12 volt as is the Netgear box, so as long as you are driving within cell range, you internet access works just fine driving down the road - kids loved it.