samsung s3 unlock in blue swap for iphone +

hi i have for swaps a samsung galaxy s3 in blue fully unlocked. it comes fully boxed with all accessories and also the limited edition olympic case. wanting to swap for iphone 4/4s must be unlocked or on 3...... dont ask to swap any other phone i simply want IPHONE 4/4S if is a iphone 4 wood want a bit of cash as they sell about 200-230 and i no samsung s3 sell for 300+