Here is an interesting blog with information on the buying and selling of CD's a la Magnatune, where the buyers choose the price they want to pay. The suggested price is usually $8, but can go down to $5 or up to $10. The demographics are interesting, as well. PayPal accounts for only 20+% of payments, while VISA hits much heavier.
Also: We have installed Haloscan for messages and trackbacks, and we lost some comment links in the process...sorry. Plus, we are still trying to hack out a permalinks aspect to this.