There’s a host of ways to get Skins and Gear in Mortal Kombat 11. In the Krypt, you have Chests, Spirit Chests (Kenshi’s Blindfold is needed to see them), Soul Vaults (Ermacs Soul Gem is needed to access them), Shao Kahn Chests and Hellfire Chests. There’s also Kronika Vaults that spawn and disappear around the map.
Chests, Spirit Chests, and Kronika Vaults cost Koins to open. Soul Vaults cost Soul Fragments. Shao Kahn Chests and Hellfire Chests cost Hearts.
In the Courtyard and the approach to Goro’s Throne, there is a Kronika Time Vault (not to be confused with Kronika Vaults). Here, you can spend Koins to refill Chests, Spirit Chests, and Soul Vaults. Some items can only be found in repopulated Chests and Vaults.
You can also forge certain items via the Forge, which costs various items and currency, and you can gamble at the Shrine for another pool of items. As has been mentioned, 100,000 Koins is what you need to spend for Skins, 75,000 Koins for Gear. Not sometimes you’ll still get Augments, despite the spend.
In the Warrior Shrine is a wall with spikes and characters faces. As you play the game, when you perform your 25th Fatality on a character, you collect their Head. You can then go to the Krypt and place their Head on a spike. This will unlock the Chest there for that character and grant you some items and an additional Intro and/or Victory pose. Impale, I believe it was 10 heads, and the doors to Shang Tsung’s Throne room opens, allowing you access to some great chests that contain intros and victory posses as well as other items. I believe 15 heads total opens another set of doors, and finally 25 heads opens the last set of doors in his Throne Room.
Also, when you put on Kenshi’s blindfold, you’re sometimes attacked by a zombie. Kill it with your Hammer first, and you’ll get a Sub-Zero skin. Find Reptile and kill him with the Hammer (he’s also invisible), and you’ll get a Scorpion skin.
You also get Skins and Gear via completing Towers in the Towers of Time, by playing through Story Mode, and by winning AI Battles.
For those who haven’t, you can go to testyourmight.com to find Forge Recipes, and other useful Krypt stuff.