BLACKBERRY 9780 SWAP FOR I PHONE 4 + CASH FROM ME -

I have a blackberry 9780 that i would like to swap for an I phone 4. Comes in box with accessories. The phone has been with me for 10months it is a contract phone that I am looking to change and I want something new. I am looking to put down an amount that will justify the swap so if you are interested please contact me asap! Thanks