Horrible iTunes error! Please help!

My iPhone is rebooting from 5 to 10 minutes so I put it on Recovery Mode when this error appeared. My warranty certificate expired and I cannot use and also I think that the cost of reparations is pretty high. Is there a way to fix this error? Can I repair my iPhone by myself?
Thank you experts!

The iPhone “iPhone” could not be restored. An unknown error occurred (13).
