Cheat mode
First thing to do is select career mode and choose any wrestler. Then during career mode, enter one of each of the match types. You can either finish the match or exit right away. After all match types have been entered, a message stating that the cheats can now be bought in the shop will be displayed.

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

Bruno Sammartino
First select career mode and choose Hulk Hogan. Then finish career mode to access Bruno Sammartino at the shop.

Andy Kaufman
First select career mode and choose Jerry Lawler as your wrestler. Then beat Andy Kaufman to access him at the shop.

Big John Studd
First select career mode and choose any wrestler. Then beat Big John Studd to access him at the shop.

Easy Green Coins
Enter the Create A Legend screen and  make a wrestler with poor attributes on purpose (stats are set to zero). Then beat him repeatedly in ladder and cage matches to receive three Green Coins with every win.