A new update will be made available soon for Super Smash Bros. For Wii U/3DS. The update will include free and paid content for both Super Smash Bros. For Wii U and Super Smash Bros. For 3DS.
A plethora of new costumes will be introduced to Super Smash Bros. 4. A Parker costume, a King. K Rool costume and Chrom from Fire Emblem: Awakening will be added. It is likely that the costumes will be paid content.
Two more stages will be introduced into the selection. From the original Super Smash Bros., Hyrule Castle 64 and Peach Castle 64 will be added. Again, it is likely that these two stages will be paid content.
As promised, Nintendo will be rolling out Tournament Mode and the feature to save and uploaded replays to YouTube. I suspect these two features will be free when the updates rolls out.
More content will be announced tomorrow, so stay tuned at Nintendo News Fix for all the developments.