Can i get my iphone 3gs replaced?

I have an iphone 3gs, don't be saying why have such an old phone blah blah blah, but now the battery has gotten really bad, it takes hours or a long while to turn on and when fully charged it goes out of charge at like 70%. I think i might have warrenty, am i able to get it replaced or not because they don't sell iphone 3gs in shops anymore?

Which is better: a rubber or plastic iphone case?

I have an iphone 5 and i've been looking at cases, i don't want any big otter box or anything but the case i'm looking at purchasing comes in a hard plastic or a softer rubber material, which would you suggest to be the better buy?

Under iPhone 4 home button replacement

During a replacement on an iPhone 4, the small circular silver tab under neath the home button attached to the iPhone body flung off and now the home button doesn't do the clicking. What is this part called as I'm trying to replace it.

Has anyone tried this method?

My brother gave me his old iphone4s from at&t and he said he would unlock it for me(so i could connect it with tmobile). Turns out he told his girlfriend to go unlock it while he was at work but she forgot to and then she forgot to tell him that she didn't unlock it.
i googled a way to unlock it myself for free but i just wanna know if anyones tried this and if its worked?

http://www.jailbreaknation.com/how-to-unlock-iphone-4s-no-jailbreak-gsm-only

Need some serious advice about my iphone 4s?

I dropped my iphone 4s in the water a few days ago. I left my phone in rice like people told me to for two days, but it doesn't seem to work. My contract ends in november but they said i can change my phone on july 14. I have verizon btw. I have like three weeks left, but i have some very important stuff in my phone and i'm expecting some calls/texts. Will verizon fix my phone, but more importantly, can they fix my phone? Or is it dead already?
any advice would be appreciated!

Will I get charged for texting?

So I'm from canada but I'm in the states right now visiting some relatives. I turned off my 4G and cellular data but I only texted my friend when I had Wi-Fi on. I'm worried though because I don't want to get charged. Will I? Both phones are from canada, both have unlimited texting and yeah. *TEXTING NOT IMESSAGE I USE AN IPHONE.