apple iphone 3gs on three pay and go *

apple iphone 3gs 8gb on three network pay and go this phone is less than a week old and cost me £299 but have now took out a contract and got a 4s and as i have used the phone i cant return it it has the latest software and features on like news stand and slide down notifications there are no scratches or marks on the phone it comes boxed with all accessories i am looking for sensible offers around £170