I gave $200 for mine non-working, but the backglass needed replacing. If the inner backglass is bad, stayaway from it.It took me forever to find another one. I got an NOS outer glass from PB Resource. Also, if this has sat a long time, the cpu will more than likely need replacement due to battery corrosion.
I would say if the backglasses and playfield are nice, no more than $400