Just one page duplicated? Bah. Obviously you don't want to put them in the store cheap- people WOULD buy them instead of the proper copy (I mean, one page? You can put up looking at the website version of the comic for one page). But keep them around. Use them as prizes, at cons and stuff. And when the full version is sold out, you could make some of the defective ones available if you didn't think there was enough demand to reprint.
Here was I thinking "unsellable" meant there was accidentally something really gross in there which could not be allowed to see the light of day on an Erfworld page lest it end up on Fox as "Erfworld proves that webcomic creators are Nazi sympathisers" or something like that.
Me too, that's not exactly what I would consider un-sellable but I do understand why he wouldn't want to charge full price for missprints to customers and why he wouldn't want to sell them cheaper because nobody would buy the correct version. Essentially its a catch 22.
If its just a 1 page duplication, I'd offer them as bonus copies to anyone already buying a copy of the book. Have a bunch of stickers made up saying "OPPS - we misprinted these so we're giving them away as bonus copies for you to give away to a friend", and apply 1 to each misprints cover to avoid confusion. Then buyers who buy 1 will essentially get a second for free allowing them to give a copy away to someone else, perhaps getting a new erfworld follower out of the process. The buyers can also choose which copy they want to keep for themselves, for people like me I wouldn't care about a duplicated page, but others might. The cost of shipping 2 copies vs 1 really shouldn't be that different anyways so I wouldn't expect the cost of doing this to go up much aside from the sticker production.