CreditsAPI
CreditsAPI just creates a file for every user to save his amount of credits in it. Developers can use this to make shop plugins or lobby plugins where you can buy sth etc.
For server owners
If you're a server owner just download the API and put it in your plugins folder. Another plugin maybe need this.
For developers
Just add the .jar to your build path and start using it. You can use all of this:
CreditsAPI.addCredits(Player, amount);
CreditsAPI.removeCredits(Player, amount);
CreditsAPI.setCreditsCount(Player, amount);
CreditsAPI.getCreditsCount(Player);
Have fun using it and report any bug to me with a ticket. Thanks!