How to turn my iphone 3gs back on

So last night when i woke up from my nap i was using my iphone to text on pinger since my bill wasn't paid. And my power button doesn't work so on my settings i put that after a minute of no use it closes. After two minutes later i pressed the home button to open my phone but all of a sudden it wouldnt turn on. I asked my friend for help and he told me to hold the power and home button down but as i said my power button doesn't work. I left it on my Ihome over night and even plugged it into a wall and pressed the home button constantly and it still won't turn on. I really really need help and i heard i can fix it on my own instead of bringing it into the store and getting a new one. Please help me i don't know what to do.

Added (1). And i can't bring it to the store cuz i'm 14 and i'm not old enough to get things fixed and plus its really important to turn this phone on to me cuz i can't get any other phone so please tell me ways to fix my iphone 3gs

Added (2). And it had shut off at 80%

Added (3). And its 3 years old.

Added (4). And its 3 years old.

Added (5). The power button doesn't work at all

Maybe the iphone had reached its age its too old get a new one but if you really want to fix it do this

first charge it it might be you ran out of battery

second if the first one didn't work than open your iphone and replace batteries

if none of the above work sorry but your iphone is… Dead

RIP

here lies kavons iphone 3gs

How old is your phone, though?

Try doing a full reset.

I'm a resident expert on Android phones, still new to the Apple-sphere so can't help you much.

Try holding down the power button AND the home button at the same time. Keep holding it for about thirty seconds or until the apple logo comes up.