Best affordable cell phone carrier?

My wife and I have been Verizon customers for over 20 years and, now that we’re retired, are looking for ways to reduce our monthly expenses. My mother was on our plan and recently passed away so I need to drop her line and also the line our married daughter uses (she pays us monthly). All that being said, I’m wondering which carriers other retirees on fixed budgets use. Our Verizon bill is currently around $140/month and when I inquired about dropping my mother’s and daughter’s lines, I was quoted around $100/month for just 2 lines. I’ve looked at Mint Mobile, but I’m wondering if their coverage is as good as I’ve been used to with Verizon. Any input or suggestions would be greatly appreciated. Thanks.