During a recent investors meeting Satoru Iwata has announced that starting with New Super Mario Bros. 2 the 3DS will be able to download full retail games to its system. No price point was revealed but Iwata has mentioned that Downloadable Software should always be cheaper than boxed retail versions. And in another move retailers will be given cards to sell the downloaded version via a 16 digit code entered in the eShop. It is unknown if previous 3DS gems like Mario Kart 7 or Super Mario 3D Land will be available via eShop.
And on the Wii U side of things Iwata also revealed that the Wii U will launch with a store that lets you download full retail games giving owners the choice to buy it at retail or via the online store. Again no price point was given for these but expect the Wii U games to cost more than the 3DS downloads.