audible credits

I have some audible giftcodes of 10$(worth 1 month sub) and want to sell them, so do you guys know a website or something where i can list them.

Hi, I'm still new to the forums so forgive me if this isn't the right place to ask, if it's not please move it. :) I see these sellers on eBay selling Audible credits for as cheap as 6 credits for £14, what is the deal? Credits are normally a lot more,, £8 per month for 1 credit. These listings...