Switch

Mewtwo will also be available as paid DLC in Smash Bros


Previously Nintendo has only said that people who buy both the 3DS and Wii U versions of Super Smash Bros will get Mewtwo for free in spring 2015 as a playable character. But what about people who only buy one version? It appears that these individuals will have to pay for Mewtwo.

Nintendo of America and Nintendo of Europe both say this about the Mewtwo DLC:

The character will be made available to purchase as add-on content in the future.

That settles that I suppose. I don’t think its bad to ask players who only buy one version of the game to pay for this particular character so long as the price is reasonable. Knowing Nintendo, they’ll only ask for $2-$5. They’re pretty good about DLC pricing, at least this past year they’ve been good about it.

Source