Just get the 6s+ so you don't deal with their stupid design on the 7. Apple Music gives you free music choices for 3 months then it's automatically $9.99, that way you get bored of the song you aren't stuck with it. I believe they also have student discount so it's $4.99. Battery life really depends on how much you're on the phone. You can also buy the inbuilt chargers (they are cases) for the iPhone but it won't really protect your front screen. Also the cables for the iphone are expensive to replace but seriously go into the auto department in Walmart and they are like $6+ depending on how long you get them. I got 2 10ft cables so I'm not restricted to one side of the bed.
Using iTunes isn't bad either, I find it easy to grab all the songs from CD's I bought in the past and just rename them. Plugging an iPhone into the computer to grab your photos/videos is simple by dragging the shit into a folder. That way you can have more room. Easy back up from iTunes incase you lose your shit and have to transfer to another phone. The employees I believe are limited on what they can transfer.