Figured I'd share the latest promo which is a pretty sweet deal if you're into audiobooks and have Amazon Prime. It looks like it's only for new customers of Audible, so YMMV.
You get 1 credit per month. 1 credit = 1 free eBook to keep forever in you Audible library. So you'll get 3 during this deal! You can also send them (credits), as a gift!
https://www.audible.com/ep/lto
Offer expires July 31st. First billing cycle kicks in after three month trial at $14.95 You can cancel anytime.