How to get more storage on my iPhone to download a movie from iTunes?

I've already deleted seven apps, 120 photos, 3 videos, some cache videos, and all Safari history. I'm very frustrated, I've been waiting a month to watch this movie.
Is there anywhere else I can look to delete superfluous material on my iPhone? How do I acquire more storage? Sorry if this is a stupid question, not very techno-saavy. No rude comments.

Why won't my GoPro Wi-Fi connect to my iPhone?

The Wi-Fi shows up on my phone, but when I go onto the GoPro app and try to go on to it, it asks me to change the password and Wi-Fi name. When I type in stuff to change it, it just says failed. How to fix this?

When people call me they can't hear me?

I have the iphone 5c and I've had it since christmas, it works perfectly but now and again I take a call and they can't hear me at all? I hear them just fine
I recently just downloaded ios7 would that make a difference?

Iphone 4s microphone issues?

I have an Iphone 4s with an otterbox case. I've dropped it many times since i got it but recently i dropped it and now the microphone won't work for phone calls unless i turn on speaker phone. Is there a way to fix it?

How else can I use iMessage on my iPhone without cellular data?

Because AT&T has limited data, I have to turn off my cellular data (not 3G), so it doesn't go over. I have to turn off my iMessage too because it doesn't work without cellular data. It doesn't really work with Wi-Fi either, unless I'm wrong. However, my communication through SMS and iMessage messes up a few times because the other person would be on iMessage, and I'm not. I'm just wondering if there's a way around it because it's a hassle when there's miscommunication.