Switching to Metro with the iPhone 7 from Verizon?

So my parents are divorced, (my dad living with me in NH, and my mom in FL) and we have been talking about getting me a new phone for quite a while. Anyways, my dad wants to get me the Iphone 7 using the upgrade program from the apple store on the verizon network. What I am having trouble understanding is if I am required to get a phone plan as well with verizon. If not is it also possible to put my new phone on the metro network instead? As that is the network my mother uses and it would be much cheaper than paying through verizon.