Can the Apple store replace my Iphone?

My phone broke a few days ago. It just shut off and started flashing the apple symbol. Its been like that for 4 days now and i've tried everything to fix it. I'm bring it to the Apple store today but i want to know if they can replace it there and how much it will cost.

If i upgrade to iPhone 5 how long til I can downgrade?

I really like my current phone and want to buy the new iPhone 5 but not yet use it… Maybe in a couple of months. I'm eligible for an upgrade. So can I downgrade to my old phone the same day I activate the iPhone 5?

What apps use data on my iphone 4?

Like for an example does the kik app use up data? Pandora, facebook, twitter, oovoo? Cuz i'm getting an iphone but the problem is if i go over my data i will get charged more so i wanna know what apps not to use without Wi-Fi

Iphone carriers, does it matter if its different?

My brother gave me his old Iphone4. The carrier is AT&T I have sprint. Can I still change it over to my plane? I didn't think it matterd since people buy Iphones over the internet all the time. We already have 1 Iphone on our plan(my husbands)… So is there a difference?

My iphone has stopped working? - 1

I was at work listening to music on my iphone 4 and i paused it with the pause thing on my headphones so i could help a customer,

so when the customer left i tried turning it back on with the pause thing on my headphones (the music not the phone)

then it didn't play so i got out my phone and it was off, black screen no power warning i know it was 80% when i looked about 5 mins earlier so was confused, left it till i got home and i've charged it for an hour nothing is working i can't turn it on or anything, i duno what has happened

was wondering if anyone else has had this problem and if so what they did

My iPhone 5 on iOS 6 won't connect to Wi-Fi?

I'm trying to connect to a new network but when i type in the password to connect it says incorrect password. It connected to my iPad fine though. I'm trying to connect to a bt Wi-Fi.