Some recent serious games auctions on eBay:

Serious Games 1st ed. 2017

$95.24
End Date: Saturday Jan-13-2018 6:03:39 PST
Buy It Now for only: $95.24
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SERIOUS GAMES - NEW PAPERBACK BOOK
$52.01
End Date: Saturday Dec-16-2017 14:53:15 PST
Buy It Now for only: $52.01
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Serious Games, Exergames, Exerlearning
$39.74
End Date: Tuesday Dec-19-2017 17:54:49 PST
Buy It Now for only: $39.74
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SERIOUS GAMES DEVELOPMENT AND APPLICATIONS - NEW PAPERBACK BOOK
$82.19
End Date: Saturday Dec-16-2017 15:56:31 PST
Buy It Now for only: $82.19
Buy It Now | Add to watch list