Donkey Kong dual screen game and watch price range?

[Blitzwing256]

A friend of mine has a dual screen donkey kong game and watch It has the battery cover and only minor scratching on the outside. assuming it works what is a good price for him to sell it (to me) for? and if it doesn't boot up what is the range for it, I see a few on ebay going for around 60, is that a fluke or the average going rate?

[MarioMania]

If it's $60 on ebay, ask like $36 or $40 if it doesn't work $20

[Baloo]

With battery cover, $40-60 is fair.