There was a way where if you edited WillowDLC.ini and edit the line +NumKeys=X you'd get however many keys. Well they fixed that but I just figured out a way to get more.
First start off by going to
C:\Program Files\Steam\steamapps\common\Borderlands 2\DLC\POPremierClub\Lic
Open WillowDLC.ini with notepad or Word
Located the line
+SourceId=254
Change that by 1 number up. So +SourceId=255
Save
Load up Borderlands 2
Continue your game
You should get a pop up saying how many keys you have now.
Each time just edit the SourceID by one number.
So..
Close the game
Edit WillowDLC.ini
Save
Load Game
Continue Game
So on and so forth