Gold credits can only be purchased for real money by spending users and can be converted back to real money by Sine Wave virtual goods partners.
Gold credits trade at 10 / 1 fixed ratio with USD$
Silver credits are free promotional credits given to users as rewards for participating in the community.
Silver credits cannot be converted to real money but can be used by creators to promote their content to new platform users who have not yet purchased gold.
You can set each item you want to sell to gold only, silver only or any combination of the two.
As a guiding principal we would recommend making most of your inventory gold only but offering a few items for silver as well, perhaps 10% of total inventory, to help promote your goods to a wider audience and to give the platform a richer pool of content for new users to explore before they buy gold.