It's probably a good idea to take extreme care of your current Wii U GamePad, as a replacement from Nintendo will cost you $150, according to one NeoGAF user.
User nbthedude shared his story on the forum, along with his receipt, and said that after Delta Airlines lost his luggage -- which included his Wii U power cord, sensor bar and GamePad -- he had little choice in where to turn for a replacement. Nintendo sells the controller itself for $140, and not the rumored $80 nbthedude said he read about prior to purchasing. After taxes and shipping his total bill came out to be $155.15.
To put it into perspective, that's half the price of the Wii U 8GB Basic Set, and as of this post, $60 more could nab you a PlayStation Vita and a game at Target, as nbthedude pointed out. Oof.