Do I have to use the $45.00 plan?
I currently use the 35.00 plan and do not have a smartphone. If I upgrade do I have to pay more for my plan?
Smart phones provide POTS, Plain Old Telephone Service, as well as all the fun things that endear themselves to so many users. No, it is not necessary to upgrade Verizon service to use the Moto e phone. You will be able to use it as a regular phone and can still enjoy the smart phone features, but NOT text, when you have WiFi access.
If you want to text and use apps when not in a WiFi zone, then a plan must be purchased that supports these functions. There ain't no such thing as a free lunch.
TANSTAAFL
P.S. You could consider using another carrier...