I know so little about these things. And I am very happy with my decision to go with Verizon unlimited data plan. I use my phone to tether wifi (or however this is properly phrased) so all my phone service and internet is through my phone via Verizon unlimited for $55 / month! Seems crazy to me but its true. I work from home often and wifi is fine.
I’ve been very happy with Mint Mobile for the past couple of years. I pre-pay for the year and it works out to something like $25 a month with plenty of data, calls, and even cheaper international calls. But I think you can also do three month intervals. They operate on the T-Mobile network so coverage is great. After over-paying for years on Verizon I regret not trying them sooner.