Depends what bitrate, if you are going to compare it vinyl.
I'd say to play something out you want it to be at least 320k
Or choose a format that entails no loss of quality.
MP3 is just a compression format. For your average kiddie listening to coldplay through shit earphones on an ipod you don't need much more than 128k.
Playing 128k through £5k amps and 10k speakers you are going to notice a lot of difference.
I'd pay £1 per track & more for an EP with artwork and a biog. People like content, offer it up and people will pay for it.
Like you said, paying £8 for one track is too much. And the days of getting rinsed like that are over.
Ultimately the digital revolution should empower the artists and the labels, and utterly shaft the huge distributers and corporations.
The currency the bigwigs trade in is disappearing, and they need to reinvent themselves and offer something valuable. The means of producton are now open to all.
Change or die.