You have to get your sellers wings before you can put a gin on your auctions. I think it is 10 auctions but I am not sure. You will know you can put a gin on something when you go to post something and in the advanced section, where you select the starting amount there is also a part for you to put in a gin amount below the number of days. It does cost credits to list something with a gin just so you know. Also, because some people do not know this, the lowest amount of credits that a person can enter as a gin amount is 2000 credits. The "cost" of using gin is 10% of the gin amount. I think you receive it back if the gin is used though. I am not positive on that last part though. Hope this info has helped you out some!