It depends on which parts of the aircraft it is in! If it light surface corrosion it can be blended out to a certain degree specified by the manufacture.
If its exfoliation in primary structures that will need to be replaced that can not be removed or dismantled easily it can cost a fortune due to labor and parts!
Some aircraft metal types are much worse than others and some batches of spec metals that aircraft have be made from also worse than others. If it is exfoliation or intergranuler due to metal type or bad batch the aircraft could riddled with corrosion.
When the aircraft starts being striped down you will find it around fasteners, between skins and all the little hiding places. Your hangar visit could be become very expense.
Unlike general corrosion caused by environment, ie surface.
Exfoliation can be fatal due to corroding from the inside out being unnoticed until it lets go!
Not trying to scare you from the purchase just educating.
If its all secondary structures,ie eng cowls, wing to body fairing, easy to replace. No problems