Injustice 2: All Premier Skins Ranked (And How To Unlock Them)
6. Golden Age Flash (Flash)
How? A random drop OR pay 6000 crystals.
Going forward, we need Golden Age versions of every character - many such as Batman already come with colour schemes that harken back to their earlier, less serious days. Flash though... ooh boy, let's just say you had to be there.
Regardless, obtaining Golden Age Flash might happen very early on as the outfit is a random drop, but you can also speed up the process by blowing 6000 crystals inside the Customisation menu.
Just as a reminder, you will acquire Source Crystals as random drops the more you play, but in true Warner Bros. fashion, 6000 is just enough of a grind to tip the balance of most peoples' willpower into opting for a microtransaction instead - especially once they've unlocked the first two or three.