UPDATE: Appears you can get one of the following:
-3 months of Gold for $7.49/month
-1 free credit
I've been with audible for a while and spent some bucks with them so this may not work for everyone, but if you have a membership and have had it for more than a couple of months this will probably work, and is worth a shot.
- Log into your account and in the upper right hand corner of the screen, click on the membership plan listed between your name and the number of credits you have.
- Click on "Change my membership"
- Down at the bottom of the screen, click "Cancel Membership"
- The next screen will present you with a drop down box and ask why you want to cancel. I chose "My membership plan doesn't work for me." I'm not sure if your selection matters, but to be safe you might want to duplicate my choice. Click "Continue."
- On the next screen, Audible should offer you a $20 credit towards your next purchase if you agree not to cancel. Agree, and on the next screen load you will see it listed in the "Available Balance" in the upper right of your account.
*Note - if you have credits available and you actually go through with the cancellation, you will loose them, so don't confirm your cancellation unless you spend them first!