A pay-per-play pricing model

I've decided against signing up for a premium account at the moment, because I think it's a little too expensive. I already have a library full of my favourite music, of course, so I'm using Spotify to try out albums that I'm thinking of getting. I'd like to get rid of the ads, but I think the monthly fee is too much for the amount that I will use it (especially considering that I'll buy the albums I particularly like, anyway).

What I would like is a pay-per-play pricing model: say £0.02 per song play, paid for out of a top-upable balance (with a £5 minimum top-up, but with small bonuses for topping up larger amounts).

Then, you should keep track of how much is spent on each song and album, and allow me to apply that amount as a discount against buying the song/album at your partner retailer. Purchasing should also make that song/album play for free in Spotify from then on. Yes, it would a nightmare to coordinate all that between the publishers and retailers, but if you managed it your world domination would be assured. :-) In fact, it might be simpler if you cut out the middleman and started selling MP3 downloads yourselves.