Is iTunes safe to download on a laptop w/ only Norton Antivirus? How does it work?

I recently just got a laptop (my desktop cmp is really old and having problems) and I wanted to start downloading music to put on my phone. I know that LimeWire is no longer available and I don't know of any other safe & reliable download programs that have free music downloads so I was thinking of doing iTunes. I've never used iTunes before so once I download it, how does it work? Is it very expensive? I'm honestly not interested in paying out the *** for music I can download for free somewhere. Please help ASAP, thanks so much.