From the article:
Fortunately, much of that wardrobe will get to make its way into fans' hands.
Maynards Liquidation Group is having a massive sale on clothing used on the show, including costumes worn by Padalecki and Ackles. It will also probably include several trench coats worn by Castiel (Misha Collins), along with costumes worn by guest stars and background actors.
Supernatural Is Selling Off Its Wardrobe Department There won't be "one original" of anything, most likely. May duplicates of each costume (including Castiel's trenchcoats) are made. For one reason, on SPN clothes get torn, filthy, etc.
It's going to be a MADHOUSE!