Grey and darker grey screen ? Only when reconnecting to a charger?

my friend wants to give me a MacBook Pro for 100 dollars that only boots a grey screen with a darker grey vertical line on the right side of the retina display. He said he had dropped it and never tried to fix it. There is a crack on the back right of the Mac. The Mac only boots to the screen when I plug in the power(Once every time I reconnect it). Though the charging indicator stays off. Is it worth the 100$ alone or should I not even try to buy and fix it at this point?