In addition to including a sweet stand, the fancy $350 Wii U Deluxe Set will include a two-year-and-some-change membership to “Nintendo Deluxe Digital Promotion.” For every 10¢ you spend in the eShop on the Wii U, you will earn a point, which can be redeemed for 1¢ to spend in either the 3DS or Wii U eShoppes.
For example, spending $59.99 on New Super Mario Bros. U, the new Mario game on the Wii U, you would get 599 points back. You can then transform 500 points that into a code that you can put into your eShop account, probably by typing in a series of letters and numbers using a stylus.
From the way Nintendo words things, all memberships start on Nov. 18th, and then run for two years, no matter what the date of purchase on your console. Buyers of a Wii U with Bonus Stands in October 2014 will have a lot of shopping to do before the promotion runs out on Dec. 31, 2014. There does not appear to be any way to enroll other than buying the fancy Wii U with Blackness.
To recap, for two years and one month-ish, starting Nov. 18th, you buy things on one system, and then get codes for money back in $5 increments you can use on two systems. It’s just that simple.