Can i buy an iphone 4 without a contract?

ok heres what i want... i want an iphone 4 but i dont want all the contract fees or anything... i wanna use my iphone 4 as an ipod touch but i want the iphone .. is it possible to buy an iphone 4 without purchasing a contract with a phone carrier?? if it is how much would it be ?? i want the 16gb one .... would it be $199 or would i have to buy the iphone 4 unlocked 16g for $650... ?? person wiiht most thorough answer gets 10 points.. plz no comments about just buy an ipod touch .. i dont want the ipod touch i want the iphone ... (manny reasons why) ...