First Retailer Selling GamePads
Very.co.uk, a retailer based in the United Kingdom is currently selling individual Wii U GamePad Controllers. Right now the price for the controllers is £89, which is roughly around $145.
They claim to have the GamePads in stock and will deliver them once purchased within the UK within 2 working days. Both black and white are on the site to purchase.
This looks like a great deal if you need to replace a broken GamePad, but other than that there is no need for a second one. Most GamePads should still be covered under warranties as well, unless you did something purposefully to void said warranty.
You can view and purchase the GamePads directly from the Very.co.uk website.
The site has much more than just GamePads as well, their Nintendo Wii U section features controllers, chargers, cases, headsets, and even toys based off of Wii U games. For those procrastinators this could be the perfect place for some last minute holiday shopping.