Iphone off ebay a good idea?

Do you think it would make a difference if i got an iphone on online ebay, verses buying a new one, what sucks is i've been with sprint since 2008 and if i wanted to buy an iphone with out an upgrade is 800 and with an upgrade you still have to pay extra, i'm seeing all these iphones between 200 too 300 dollars and that seems kind of good?

Why won't my Iphone 4s show that it's charging when plugged in?

I just recently bought it (unlocked so I can use it for T-Mobile) from a friend of mine and he told me that when you plug it in to the charger it doesn't say it charges but it does actually charge. I plugged it in and like he said, no icon appeared that indicated it was charging. I have to constantly keep checking the percentage to see if it really is charging. I also noticed that it takes forever to fully charge… For example, when I first got it it had about 25% battery. I charged it for the night and in the morning it only had 57%. I used it for a little (texting, facebook, etc.) and the battery immediatley dropped to 20%. Its been charging all day since and at 20 minutes to midnight its only at 56%. Why is this happening and what can I do to fix it? I've used multiple USB cords/outlets/computers and nothing seems to work. I've tried cleaning all the USB's as well.
Is this a problem with the battery itself? If so I don't understand why no device (USB, PC) can recognize when it's plugged in. What can I do to fix this?

How to avoid paying for data on the iphone?

I'm getting an iphone this week and really don't want to have to pay for data. Does the enable 3g button under settings work? (It's a 3g) so is there anyway to just not pay for it?

Why is my Iphone 4 not charging

I've had this iphone for only about 2 months, dropped it a few times and isn't even cracked. Today just out of the random is stopped charging, I tried everything wall chargers, car, ihome compuer, different wall chargers, nothing charged it. I think i'm gonna go to apple tomorow but if any of you can give me a soution and save me a trip that would be amazing.