What iPhone 5 S storage do I get?

I wanna buy an iPhone 5S but I have no clue what 16GB, 32 GB, AND 64GB mean. Is 16 enough? How much photos and apps can that hold? Is 32 the better choice? Or 64? I have no clue what'll happen, I may want to go on instagram and upload pics every day or maybe I want a lot of apps some day. Don't know. I like to think I should go for 64GB just because I've been saving for the phone and a lot of space is what I should get because of that! I think it'd be nice to be like "oh I can get this because I have so much space!" I don't know, everyone give me advice.

My Iphone won't get texts outside Wi-Fi?

I had a phone that I the sim card traansfered to put on another sim card for my IPhone. I have calling, sms, and unlimited data. However when I leave my house I can only send texts and I won't receive them?

How to clear the other data on an iPhone?

My storage space was 4.0GB left. Then it suddenly just dropped to 412MB left. I don't know why, but I'll bet it's because of the "other" data, as the apps and photos and stuff take up only enough to allow 4 GB left. Where'd all my space go and how do I clear this "other" data?

Can I use a used iPhone as a prepaid phone?

I have a used AT&T iPhone and I want to use it as a prepaid phone. It's my boyfriend's old phone and I'm going to use it because the phone I have now is old and slow. Can I activate this as a prepaid by myself or do I have to go to AT&T for that? He has a new phone, and he kept his same number, so would I have to activate the SIM card or buy a new one?

I know you guys aren't AT&T techs, but any information you could give me would help. If I have to go to AT&T, then I have to go and it's whatever, but I was going to try to activate it as a prepaid by myself through the website, if that's even possible.

What are some music apps to where I don't need Wi-Fi to listen to the music?

So I have an iPhone 4 S and I need a music app that I can listen to music on. The thing is, I won't have internet everywhere I go so I need to be able to listen to the music without Wi-Fi. Anyone know any good apps? Please and thank you.

Added (1). I DO NOT USE ITUNES I DO NOT WANT TO PAY A TON OF MONEY FOR All MY MUSIC I NEED

Help IPHONE 5S APPLE ID PROBLEM?

Okay, so i had my iphone 5 stolen around two weeks ago and i finally got it back. The person who had taken it COMPLETELY RESET THE ENTIRE PHONE! And i can't get pass the part of the phone where you have to put your apple ID an Password in ( it's there because i have track my iphone) But i haven't used the email in god knows how long so i have no idea how to get this problem solved… Please help.

App to store delted photos in?

What's an (iphone)app that i can put photos into? There are some selfies i don't want in my camera roll(i'm insecure)but want them on like an app or something