Board Thread:Questions and Answers/@comment-33149505-20180217165437/@comment-32271305-20180217172734

One unit is free, but most of them are either Dokkan Fest Exclusives, like the ones mentioned below, or non-featured SSRs on every banner (as rare as an LR, basically). These are currently the easiest ones to get:

will be released on the 21st, and he's the only free INT unit with Fierce Battle.

can be bought with a free Red Stone, as soon as they release the next one.

are currently on PHY Super Vegito's banner.

will be released in two weeks on his own banner.

will probably be released two weeks after Frieza on his own banner.