I've read stories over the years where those things have sold for hundreds of thousands of dollars at auctions. I wouldn't be surprised if if reaches at least $250,000, maybe even more since it's verified as working.
A few weeks ago I was watching an old video clip of Steve Jobs from sometime around 1980. Somebody asked about their upcoming products. This was followed by the question of whether the Apple II would be prone to early obsolescence like the Apple I, and quickly lose software support.
In an effort to reassure people that their investment would not be a waste, Jobs explained that the Apple I's abandonment was a special case, and that owners of the Apple I had been offered a discount on upgrading to the Apple II.
Damn, I feel sorry for the guy who took that deal.