iphone 3gs for sale !

i have a iphone 3gs for sale unlocked to anynetwork boxed with everything! 16gb and comes with 2 cases just brought a brand new white back for the phone which havent been put on up to buyer to put on! it needs a new screen i think? as when turned on screen go white n stays white! may not need new screen i dont have a clue reason why £100 need gone asap! call or text or 07773344466