Found this on another site, works for me...sorry if it's been posted already
his is a very simple guide on how to get an infinite number of golden coins in Borderlands 2.

If you have Borderlands 2 premium (doesnt matter if its pirated or not), get in that folder and open DLC - POPremierClub - LIC

You will find a config file named "WillowDLC"



Now usually the file would be like this:


[GoldenKeys]
+SourceId=254
+NumKeys=1 (change this to the number of keys you want, from 1 to 255)

[PromotionalUnlocks]
+UnlockId=2

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