iPhone 4 on Voda. Sale or swap !

Hi. I have a immaculate iphone 4 16 gig that is locked to Vodafone. It is in pristine condition and has not been used after having a new screen and digitiser fitted (I did not know it was locked until then). I will swap for similar unlocked or on "3" or an ipad. Any thing else considered, i.e. Moped etc etc, please ask