This is an easy one. There are 26 costumes to buy in the Krypt. you need exactly 28,980 koins to buy all of them (Cyber Sub-Zero is the only one without an alternate costume). You DO NOT NEED Mileena's 3rd Alternate Costume to gain this trophy.
Kratos's Alternative Costume: Finishid the ladder with normal costume of Kratos
Deadlands:
Reptile - Egg of the Last Saurian - DL-7 (1160 Koins)
Johnny Cage - Cage's Sunglasses - DL-15 (1200 Koins)
Sheeva - Sheeva's Shokan Talisman - DL-28 (1200 Koins)
Baraka - Baraka's Blades - DL-40 (1080 Koins)
Sektor - Sektor's Rocket - DL-47 (1100 Koins)
Stryker - Stryker's Baton and Pistol - DL-56 (800 Koins)
Quan Chi - Quan Chi's Amulet - DL-63 (1500 Koins)
Kitana - Kitana's Fans - DL-69 (1200 Koins)
Kabal - Kabal's Mask - DL-88 (1200 Koins)
Shang Tsung - Shang Tsung's Soul Amulet - DL-101 (920 Koins)
Nightwolf - Nightwolf's Tomahawk - DL-110 (1060 Koins)
Scorpion - Scorpion's Spear - DL-119 (1500 Koins)
Hollow of Infestation:
Liu Kang - Liu Kang's Inner Dragon - HI-8 (980 Koins)
Sonya Blade - Sonya's Dog Tags - HI-22 (800 koins)
Mileena - Mileena's Sais - HI-33 (1140 Koins)
Meadow of Despair:
Cyrax - Cyrax's Bomb - MD-6 (1200 Koins)
Raiden - Raiden's Thunder - MD-14 (940 Koins)
Kano - Kano's Knives - MD-25 (1200 Koins)
Jax - Jax's Flag - MD-36 (1200 Koins)
Sub-Zero - Grand Master's Amulet - MD-54 (1000 Koins)
Bloodmarsh
Noob Saibot - Noob's Shadow - BM-5 (1040 Koins)
Sindel - Sindel's Crown - BM-19 (1200 Koins)
Kung Lao - Kung Lao's Hat - BM-38 (1200 Koins)
Jade - Jade's Gold Necklace - BM-50 (1000 Koins)
Ermac - Ermac's Soul Trap - BM-68 (1200 Koins)
Smoke - Smoke's Cloud - BM-82 (960 koins)