If you use WiFi much or almost all the time, you may not need unlimited data. just get one with a few GB, and it should be fine. in some packages, you can restore unused data every month of the year.
If you know you will not be using Wi-Fi, download content in Wi-Fi mode to watch offline so you do not use the data. music streaming hardly uses data.
there are many variations for a phone plan. so it's hard to say exactly what it will cost. Plus, you have to think if you want a contract, a month or another plan.