I think the overlooked part here are transaction fees. Fees that seem reasonable on a $15 purchase can become significant on a $0.01 purchase. Also, transaction fees are a loss realized when selling and due to loss aversion, people may (unreasonably) refuse to sell. And finally, if you purchase a song for $0.31 (gross) and expect to sell it for $0.01 (net), the economics of this model look much less promising when compared to buying mp3's (breakeven at ~4 "listens") or paying monthly for a streaming service (breakeven at ~45 "listens"/month).