I really dislike purveyors of audio fiction who don't provide an easy way to download .mp3s of whatever you've bought. Case in point: Serial Box. I love their serials, and buy them with real money, but in order to download them onto my .mp3 player, I must either use their app---difficult, since I don't have a smartphone---or else go to the page source of each episode, search for '.mp3' in the source code, extract the url of the audio file from the page source code, and then download it that way. I mean, I do it, but since I've already bought and paid for the audio files, why can't I just have them?
On the other hand, when I borrow audio books from the library through Overdrive, I get the raw .mp3s with no difficulty, and can save them and transfer them with no problems, and keep them well after the loan period expires. That also seems wrong.