Hard to say. But if I HAD to place a bet, i'd say at least 30K. But before all of that, Bitcoin's core dev's really need to fix the high fee problem and address the other major issues. There have been many recent problems regarding the fees. So bad in fact that there have been a lot of places either stop accepting Bitcoin, or moving to other currencies...
MisterCoin-
It's really impossible to tell this. Making predictions is easy but the accuracy is sometimes very low because whales are making weird and strange actions. They are the game changers. My prediction is $29,000 for the end of 2018.