What can you guys tell me about an iPod

My 9 yr old asked for an iPhone so he could listen to music - So I looked into the iPod a little

Do you need a data plan?
Do you download and own the music?
If you're at home on wifi can you access the internet?
32GB or 128GB? Seems odd there isnt something in between -
Are these normally a Black Friday deal?

Anything else I should know?