Music
Rex Features
The band released In Rainbows via their website, telling listeners they could contribute a sum they felt was appropriate.
But Allen insisted the move makes it tough for new groups to compete because Radiohead have the luxury of earning a fortune on tour.
She said: "It's arrogant for them to give their music away for free - they've got millions of pounds. It sends a weird message to younger bands who haven't done as well.
"You don't choose how to pay for eggs. Why should it be different for music?"
Rapper Jay-Z recently spoke out in support of the idea, describing it as "genius".
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