My Guess?
$550/BTC
The price is now almost at $500 so I think that the price at the end of 2016 will be around $600 or $700 if the Bitcoin price keeps rising. But higher then that I would not go.
many say that the price of bitcoin will be higher when halving comes so lets see price after halving. maybe I could predict more easily when halving already occurred. because after halving give much influence to the bitcoin. I would probably agree with the price between $600- $700