Easy Koins
This trick requires a memory card in controller one and nothing in controller two. Duplicate the saved data from the game from the memory card to the hard drive. Load the game and the screen after the Midway logo should be that of two memory cards. The one on the left should be the one with your data from controller one and nothing will be showing in the other. Start the game and go to versus mode. Enter the profile code that you created (this information will automatically pull the data from the memory slot of controller one. Then, use controller two and input the same profile code. This will pull the data off the hard drive. Press R to make the wage bar appear on both controllers. The wage screen will appear. Wage off the maximum for whatever Koin you want to choose, and agree on both controllers. The game will then return to the character selection screen. Choose any character for both controllers. Win the matches with controller one. After you win the two matches, you win the money and the data will save to controller one's memory card. Keep betting, fighting, and winning until you get all of the money from controller two. Then, exit the game and eject the game disc. Go to memory option on the screen and delete the data on the hard drive. Note: Make sure it is the small Mortal Kombat symbol inside the bubble and not the large one on the left side of the bubble. Back out and go to the memory card. Look for your data and copy it over to the hard drive. After it saves, back out of it, close the disc tray and start again. Repeat this procedure to get as much money as needed.
Create two profiles and win some Koins with both. Go to the versus screen and load both profiles. Press R to wager. Max out the bet and press A to return to the character selection screen. On one of the controllers, press L to clear the profile, then press L to load that profile again. Go to the wager screen and you will notice that the amount of Koins has changed. You can repeat this as many times as desired. The Koins will be awarded to you once you win the match.
Note: This trick requires two controllers. Select versus mode and load a profile for each fighter. Each fighter must have some number of each Koin. Do a Wager then after that match is over, have only one player press R. Press Right and you will hear the sound, then press Up to bet Koins. Press R again and play that match. The winner will get the coins, but the loser will not lose any. Go back and forth with each fight to make each gain more Koins, thus making each match worth more because you can wager more. Keep holding Up until you do not hear the sound anymore to bet the maximum amount in time. Use the following to learn what Koins you are betting, as you will not be able to see.
Press Right, Up: Onyx
Press Right(2), Up: Jade
Press Right(3), Up: Ruby
Press Right(4), Up: Gold
Press Right(5), Up: Platinum
Press Right(6), Up: Sapphire
Start a new profile and earn 93 Jade Koins. Then, go to the Krypt and buy the following koffins immediately after each other: "FN", "UV", "ZR", and "JJ". You will now have over 1000 Sapphire and Jade Koins. Go to versus mode and bet the money to you profile. Do this as many times as desired.