How to unlock the iPhone 4, for free?

So I bought an iPhone 4 from a friend of mine and I'm wanting to unlock it so I can hook it up through a different carrier, are there any free ways of doing this? Please and thank you!

F.u. MANUEL, question contained "for free".

HI free unlocking services are not available for iphone. So if you want to unlock iphone 4 from network lock. Then have a look at sites like http://www.classicunlocking.com/apple-iphone-4/rs1wp9/ here they are rendering remote unlocking service to unlock all model iphone from network lock. You first verify that whether they are rendering service for your country and network provider. If yes then pay for it and unlock your iphone 4…

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