How much is a Minolta SR-2 worth?

I just stumbled upon my grandfather's attic this week and found probably more than a dozen Minolta SR-2 (Brand new in box). I took one out and it looked pristine and it had no use marks and it even had every manual and leaflet with it. It comes with a 50mm rokkor lens.

(My grandad use to run a camera shop in the late 50s-80s until it closed in 1987)

How much can I sell these each? I plan to keep two, though.
Added (1). I just tested one of them, the shutter works and it advances. The lens has no obvious dusts. The boxes are undamaged since it was inside a larger box
Added (2). Sorry, it isn't a 50 it was a 55mm lens.
Added (3). No. I didn't ask a question about this camera a few weeks ago, in fact this is the first question I asked since I found the cameras

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