How much data does it take to download an iTunes library onto a new iPhone?

I'm getting an iPhone later today, and my mom mentioned to me that it costs data out of our plan to get the iTunes library that I already have started onto my iPhone… So does anyone know exactly how much it'll take?

More than we have.

Depends on the size of the library

if you have 12gb of data in your library, it will take 12gb of data to download

It really depends on the total file size of all iTunes purchases if you want to use your own data allowance to get the tracks and apps straight to your phone.

If you're in a free hotspot area (like in the Apple store) you can download the library that way (which takes forever when downloading more that 2GB of data. Or just wait till you get home and sync your library with the iTunes library on your PC (quickest and cheapest way)