For anyone who is a fan of Brandon Sanderson and also an Audible member, they're offering a free copy of the short story "Mitosis". It's set between the first and second books of the "Reckoners" series, his post-apocalyptic superhero series. I haven't listened to it yet so i can't say how spoilery it is for the first book if you haven't read that yet. I don't know if there's an expiration date to the sale, or how much it was/will be when not on sale. But i often find short works on Audible to be ludicrously expensive compared to the length.