I'm running an older WiFi Ranger GO indoor router that can pick up park wifi, when available, and also switch to a cell hotspot when there are bandwidth or connection issues. My hotspot is an extra cell phone that I leave in the RV, always on a charger next to the router.
My router cost about $100-150 when new, my phone was an extra one we had in a drawer. I use Google Fi as a cell provider, and pay $25+$15+$15 for putting my phone, wife's phone and the RV phone on the plan. Data is charged only for what we consume at $10/Gig, with a cost cap at 12Gig. After that, the data is no-cost, but supposedly throttled back to a lower speed. Even beyond the data cap, we have never had issues streaming movies.
We have streaming accounts with Netflix, Hulu and Amazon Prime at home. These are available while traveling at no additional cost. We also have a Wineguard antenna on the RV roof for getting local TV channels, when available.
So, for a big month traveling and streaming movies, we pay $55 for our phones and $120 max for our data.
Good luck on your choices.
Karlos and Dawn
2007 Dolphin 5342 Workhorse
2013 Fiat 500C Toad