Can you buy a contract Iphone and get it as a prepaid phone?

Okay so Black Friday is coming up and Iphone 5 are going on sale and it is a contract phone. Would it be possible to buy the phone and have it as a prepaid phone? I would like to get it on straight talk Please Help! Thank you for your time.

Added (1). I don't have a contract with anyone like Verizon At

You can use it as a prepaid phone after you have paid off your 24 month contract.

Boost mobile i hear will be releasing it. It would be the full priced phone of course but you would owe nothing after paying it off.

You can use it with Flash Wireless no contract, as long it is a phone from Verizon or Sprint.

http://superbutilities.shopacnrep.com/wireless/index.aspx