Can I upgrade to an IPhone 5s?

I have an iPhone 4S and my birthday is this month. I don't know how phone upgrades work. If I pay the 200$ dollars for the 5s can I switch it with my current iPhone

How to get AT&T to lower my bill?

I'm with att for almost 4 years. I have 4 iphones with them. I went in to a sprint store ant they can lower my bill with about 100$ a month and give me unlimited. Now I don't want to leave att but if they don't lower my price I will.
How do I get att to lower the price?
I tried changing my plan with att but I didn't help. I use a bunch of data.

Is buying the iPhone 4S now stupid?

I currently have the iphone 4 for almost 2.5 years, works great not slow, however a small crack on the screen that it is worth 90 bucks to repair. I thought of buying a new iphone 4s faster and more storage bcuz my phone is 16gb.

i saw the iphone 5 didn't really like the long screen and light weight, felt like a fake phone and i guess the new one is the same.

the reason i'm considering the iphone 4s now its not just about the price but bcuz i really don't care about other specs, i'm a light user: text, email, twitter, music.

What do you guys think is it worth it?

Will apple replace my iPhone 5 for this?

So I was watching a YouTube video and it went to the black buffering screen it was then I realised I had a dead pixel and I've only had the phone 2 months unluckily for me now that I've noticed it I can't not see it when I'm using my phone now so will apple give me a new phone or at least professionally repair my current one?