I picked up a brand new Wii U Pro Controller off eBay for a much lower price than what most sellers are asking for. However, these controllers still have a ridiculously high resale price. It must be related to the console being Nintendo's worst-selling system outside of the Virtual Boy. Supply must be low.
I didn't buy one of these back in the day because I had no real use for it (the Classic Controller worked fine), but I would like to visit fellow Youtuber Keet next year, and well, let's just say I need all the controllers I can get for some multiplayer recordings.
