Iphone 5 won't play videos on 3G?

My iphone recently stopped playing videos on 3G but will play them on Wi-Fi. It started a few weeks ago and I have reset my phone but it made no difference.

Verizons new $75/month plan fees & taxes?

I was thinking about upgrading my phone and getting and iPhone 5S with Verizon. Right now there's some deals going on. Verizon is offering the $75/month for 2B data, unlimited talk and text. Bestbuy and Walmart is offering the phone for $99.

Right now I pay $60/month including taxes for an old android on a prepaid provider.

I'm curious what my bill will be after taxes and fees with Verizon. Someone told me to expect to have an additional $25 in fees & tax! I thought that sounded insane. I will not switch if this is the case! Anyone with personal experience with this plan?

Can I upgrade my 8 GB iPhone to 16 GB at Verizon?

Okay, so right now I currently have an 8 GB iPhone 4. I've had it for probably a year and a half now & I'm with verizon. I'm having space issues because of how much music I have, & I don't want to delete any of my music. So I was wondering if I could get a free upgrade with my contract or if I would be able to upgrade to 16 GB but I would have to pay a little bit of money (and how much?).

How many GB does my iPhone have?

I have an iPhone 4s
I want to know how many GB does it have. In "About" it says that the capacity is 13.5 GB and available 7.6 GB.
How do i find out?