Amazon offers Prime members the Skylanders Superchargers: Donkey Kong and Barrel Blaster Dual Pack for Nintendo Wii U for $7.40 with free shipping. (Non-members can spend $49 or more to qualify for free shipping; otherwise, shipping adds $4.98.) That's the lowest total price we could find by $19.

Also available for Prime members is the Skylanders Superchargers: Bowser and Clown Cruiser Dual Pack for Nintendo Wii U for $13.31 with free shipping. (As above, non-members can spend $49 or more to dodge the $4.98 shipping fee.) That's the lowest total price we could find by $13. These items all require the SuperChargers Portal to be used in-game.