cynanne: Hail fellow phone minimalist!
My first cell was a tracphone flip phone, my current cell is a GoPhone flip.
Last year, I used Straight Talk's pay-as-you-go mobile hotspot that is sold thru Walmart.
The hotspot is a small sealed gadget that's roughly the size of the palm of one's hand.
I found it trivially easy to set up (it was my first), and it worked reliably everywhere I went. The one I bought is on Verizon's network.
It supports multiple simultaneous devices - I'm not sure how many, and (annoyingly) each provider has different rules/limits. It's a good question to ask.
What laptop/etc are you using now?
Most gadgets track how much data you use, and it's simply a matter of figuring out how to find it. Ok, that's often not simple.
Win10 is pretty easy, and gives you the last month.
The two big things I hate about Straight Talk (enough to switch to a different seller) are:
no data rollover (I bought the monthly cards that have specific data amounts),
no reliable & safe way to check one's data usage.
I hope to glean much info from this thread.