What is the best Cell phone plan for a single person?

I am looking to switch to my own phone plan from my families in the coming months. I am planning on getting the iphone 8 when it comes out and planning on staying away from Verizon, because of the prices. Which company is going to give me the best deal and best service for my buck for a single person.

Must have: unlimited texting, don't need unlimited calling really.

Preferred: unlimited data or most data for my buck.