The principle is OK but it would be better with more information. How do you know that you're paying the right price? For me it would the production costs + artist's rights. And for what? Compressed 128kbps MP3(yeeechh!) or good quality audio(wav, flac)? I would suggest a recommended price. It would also give a hint to know how much we are overpaying CDs for all the big company overhead?
How about the fans who would like the CD(s)complete material but don't even have a turntable? How to void paying the exhorbitant 40 quid?