If only the external shell is cracked, and the internal chassis is still good, it'll be repairable. My guess: Several hundred ($400+) US dollars at Nikon. I recommend walking it in to the Nikon service in L.A. if possible. One good thing is that a substantial amount of the internal chassis of the D750 body is polycarbonate, which can flex and recover when whacked. My D800's, in comparison, have an all[or mostly all]-metal chassis, which has been shown to be somewhat fragile. I miss my old D3 for it's heavy-duty battle-wagon body. Now is a good time to think about having a spare body.