I just paid £5.45 for my download of Radiohead's In Rainbows. How much did YOU pay?
This is genius marketing.
It says "fuck you" to the greedy record labels. It establishes a band's independence. It solidifies their fan base. And they make (hopefully) more money.
Keep an eye on the Billboard charts after October 10. This could get real interesting.
And as NPR reported, and I'm paraphrasing, a lot of record executives are shitting their pants right now.