Pre paid yearly plan

So Im recently visiting my dad and Im stayng with him for a whole year so Ill be having lots of free time. I wanted to purchase the yearly pre paid plan and pay the full price without having to worry about paying per month. After I purchase the yearly plan can I take off the credit card associated with my account and still being able to use the program? I wont be having lots of free time when I move back. Thank to anyone who can help!