A new way of selling music

It's so simple that it's suprising nobody thought about it before. Instead of selling CDs why not sell an object that can play music by itself ? Like a small 128 MB USB MP3 player. So far the price of such players is still too much. But when the price premium will be between 5$ and 7$ (without headphones) it could be worth it. Much cheaper than the whole U2 collection on the iPod.