So .. I'm looking to do what you are doing. My car has a hotspot, but it's only 3g and AT&T at $15 a month. No thanks.

I have looked at that NET10 ZTE 10gb hotspot as well.

I have a different solution:

Context: Last year, I visited London and bought a SIM card on Amazon from the "3Mobile" company. The SIM worked in Europe, but I activated and used it in the US before and after my trip. It was $30 for one month. It's for GSM networks, but I'm not sure if it's ATT or T-Mobile in the US.

That same 3Mobile company has a 24 GB in 24 months SIM on Amazon for $48 .. so, it's $2 per gig. That's a hell of a deal. You can buy more data (top up) data on their website .."Topping up" your account appears to be 1 pence (1 cent) per Meg, which would equates to 10 pounds per GB ($13 USD).

Or .. I suppose, throw out that SIM and buy another 24 gb SIM for $48. Can't get a better deal than $2 per GB.

Amazon link https://smile.amazon.com/dp/B01M3VJ2B2/

Note: I haven't tried this yet (other than my trip last year) .. but at the moment, that's what I plan to do. Just need to buy the SIM and a hotspot. (Looking for an unlocked GSM hotspot that maybe has external antenna ports, so I can improve reception in fringe areas/while driving.)