Cheat mode:
Select career mode and choose any wrestler. During career mode, enter one of each of the match types. You can either finish the match or immediately exit. After all match types have been entered, a message stating that the cheats can now be purchased in the shop will appear.

Andy Kaufman:
Select career mode and choose Jerry Lawler as your wrestler. Defeat Andy Kaufman to unlock him at the shop.

Big John Studd:
Select career mode and choose any wrestler. Defeat Big John Studd to unlock him at the shop.

British Bulldog:
Select career mode and choose Dynamite Kid. Successfully complete career mode to unlock British Bulldog at the shop.

Bruno Sammartino:
Select career mode and choose Hulk Hogan. Successfully complete career mode to unlock Bruno Sammartino at the shop.

Owen Hart:
Select career mode and choose Bret Hart. Successfully complete career mode to unlock Owen Hart at the shop.

Unlimited Green Coins:
Successfully complete career mode with all wrestlers to get unlimited Green Coins.

Hint: Easy Green Coins:
Enter the Create A Legend screen and intentionally make a wrestler with poor attributes (stats are all at zero). Defeat him repeatedly in ladder and cage matches to get three Green Coins with each win.