In the settings, try setting the Roku to only 480p or similar low level. Good enough for kids in a car. Hopefully, most of the streaming services will only stream at that level. Also, if your phone can cast to the Roku, some of the services (Netflix, Amazon Prime, and probably others), let you download to the phone ahead of time. Not sure if it will let you cast that download, though. You may want to experiment.
2 GB or 6 mo trial. However, I heard that it may be semi-affordable pre-paid... I am less worried about the Hotspot throughput than the actual bandwidth consumed. It is Verizon LTE, as is my cell phone and it has always performed excellent.
Once I run out of my data on my road trip next weekend, I just need to see if it makes sense to pre-pay ahead of time for future vacations. I do not have unlimited plans for our cell phones, and to upgrade that, it would be a monthly charge that I am not willing to pay for a few road trips a year. However, if I can pay $20 (or whatever) per road trip and have the kids happy and quiet the entire way, money well spent!!! It looks like I will receive an email with my options when I hit the data cap, so I have no idea how much the rates may be per GB.
2 GB or 6 mo trial. However, I heard that it may be semi-affordable pre-paid... [...] I will receive an email with my options when I hit the data cap, so I have no idea how much the rates may be per GB.