At Kmart
Kmart has a deal on Wii U pre-orders that can net you a good chunk of credit. If you sign up for its free Shop Your Way program and pre-order two games, you'll get $41 in credit that you can use towards buying another game. The eligible titles are linked below:
Captain Toad: Treasure Tracker
New Egg is handing out $5 credits for pre-ordering Star Fox and Toad's solo outing.
Captain Toad: Treasure Tracker