Street Fighter V DLC characters can be earned by playing the game

[poklane]

Edwardooo said:

I don't believe AT ALL that Capcom won't make paid DLC. This is the company who sold 4 differents Street Fighter IV, and a shit ton of DLC on Street x Tekken. If we don't get any paid DLC, then Street 6 will come in 2018.

They specifically said gameplay related content can be unlocked for free. Since costumes aren't gameplay related they'll definitely have some DLC costumes you can only get by paying for them.