I've been without a phone for a few years now. My replacement is an iPad mini Wi-Fi + Cellular.
How do I make it work?
TextMe app - Give me a number and you earn minutes by watching videos.
FaceTime Audio + Video - I can make calls on Wi-Fi to anyone on an iOS device.
T-Mobile offers 200MB free each month - I never use it all since I am usually around Wi-Fi. This data is used for phone calls with TextMe.
I didn't pay for my iPad, but it looks like you can get an iPad mini Wi-Fi + Cellular on Apple's refurbished page for $309. If you don't mind carrying it around, it is worth considering.