I would get
one of these phones for $20 and then connect it with
a one gig smartphone plan for $20/month.
If you already have a smartphone you can probably bring your own phone and number to their network. This is what I did.
We presently have our Galaxy S8+ phone on their 3 gig plan and are very satisfied. I don't stream much at all (never without wifi) and this plan is much cheaper than the previous Verizon plan I was on. I used it every day this summer for my duties here on RV.net plus web surfing and was never above 1 gig/month.
Always have had coverage wherever we go and now up in the Michigan woods.
Barney