If I have an iPhone 4 with a contract that hasn't expired can I get the 5?

I just got the iPhone 4 and I have a two year plan, if I wanna cancel it and get the 5, how much will it cost to cancel it and to trade my 4 in for a 5

An arm and a leg

Depends. When is your contract expiring?

It is $250 to cancel the contract. It's $200 / $300 / $400 for the 5 so it would cost you around $200 because you can get $250+ for your iPhone 4.