Add Package: add package for users to purchase credits.
Manage Packages: edit/delete/change display order for the packages
Manage Orders: manage the purchase orders for the packages, the order status can be changed manually.
Add Credit: search users and add credits to the selected user.
My Credits block, display my current credits and buy credits link.
Select Payment Gateway, select payment gateway to pay the credits.
Go to purchase, after the purchase, the credits will be added to your account automatically and immediately.
My Invoices, display your invoices info. user could pay it again if the status of the invoice is uncompleted.