I’m a new driver and i saw a car for sale but it needs a crank shaft what the heck is that and how much is it?

its for a 1991 Galant.

Crankshaft is the heart of the engine , it is the part the convert the up/down movement from cylinders to rotary movement , if this car needs a crank shaft , it pretty much needs an engine
, my advice : STAY AWAY