How do I add a sort of currency to my forum along with a store?

[Topaz98]

How do I add a sort of currency to my forum along with a store? It would be like after such and such posts the get such and such money to get a such and such item in they're inventory.

[Pedro]

You should do it by yourself. The most similar way to get it, in my opinion, is move the top authors to special groups with special permissions.