iphone 3gs 16gb easy fix *

apple iphone 3gs 16gb battery wasnt great when i got it but got worse and worse over time until it was almost only usable while plugged in but the battery is now totally dead and must be replaced as it wont even charge enough to start up the phone someone in the know could repair this very easy by replacing the battery or u could just pay the 20 to get it replaced for you. comes with charger, usb lead, and hard case screen is scratched but nothing major (you can still see everything when the phone is turned on) and there is a small crack at the top but again nothing that actually affects the use of it. phone works perfect apart from that