Mortal Kombat 1 has been criticized quite a bit for its aggressive monetization, with certain skins costing as much as $10 apiece. However, there are plenty of other ways to get free cosmetic items just by playing through the game, with Invasion mode being a great example of this. Players can unlock new skins for their favorite fighters by beating powerful enemies or by finding them in chests. In the case of the latter though, there are usually a few extra steps involved.