Injustice 2: 8 Things You Didn't Know You Could Do
5. Get A Premier Skin Without Pre-Ordering Or Buying Source Crystals
First up, know that Premier Skins are complete costume, voice and opening taunt swaps for certain characters (which you can find a breakdown of here).
For the most part they were included with the Deluxe or fancier versions of the game, but can be purchased with Source Crystals; the currency many are annoyed is tied to the game's microtransaction system. To find them, hop into the Customisation window, pick a character and go down to the 'Shader' option. For specific characters, there'll be another shader with a logo, denoting it's a Premier Skin.
However, whilst you'll continue to accrue Source Crystals just by playing (they're random drops along with standard Credits), play the Story Mode instead, as the drop-rate on Crystals is far higher, and by the time the credits roll, you'll have at least 5000 at the very least.
Many of the costumes are locked behind 6000, such as John Stewart or Power Girl, so after the story you'll be able to pick one up, or just complete a handful more matches and grab your first costume of choice.