Amazon isn’t selling the first volume of Wandering Son right now, so the third-party sellers that list on that site have bumped up the price on the book. As of this writing, it starts at $65 US.
However, smart shoppers remember that Amazon isn’t the only source for online retail. Checking the publisher’s site shows that Fantagraphics is still offering the book at cover price. If you’re looking for a copy, why not go straight to the source?
Update: Fantagraphics has confirmed that Volume 1 of Wandering Son is currently out of print, but they are working on another printing, which should be available in stores and online “within the next month or so”.