Answer:
No one really knows how much it is. Even I don't have even the slightest clue of how much his leather jacket is.
One can ofcourse put a price to valueables attached to the jacket, but the jacket as a jacket pose no real value over a similar jacket without valueables attached to it.
As a collectors item it may be worth millions but that is an artifichal value. It only shows how much certain people are willing to pay. It does only reflect the jackets "value" because of the previous owners fame and music.