I want to use my IPhone but don't need data. Ideas?

I bought an IPhone and didn't know the data package would cost an extra $30 a month. My parents aren't happy. Is there a way to not have to have data? I really don't need it or want it. I always have Wi-Fi.
My idea was to go back to the original plan that doesn't have data then register my Iphone without data. I don't know if it will work though.
Any help please?

You can usually get a lower data plan, see if they offer a $15 or $20 data plan.

It won't work. A smartphone data plan is a requirement not a suggestion.