Unlocking Iphone 4 for free is not possible so go for paid one. I would suggest the site http://www.onlinegsmunlock.com/apple-iphone-4/rs7wp9/ ,here they are providing remote unlocking service and get the service here itself and unlock it yourself using Unlocking instructions which is given in the site itself.To jailbreak it use the site http://jailbreakvault.com/