Amazon MP3 Joins iTunes with Variable Pricing
Take a look at the Best Sellers list, for example. You'll see MP3s priced at $0.79, $0.89, $0.99, $1.29. You can see some of the page above .
While you may have hoped Amazon MP3 would have maintained its pricing structure at $0.99 for everything, Amazon was probably pressured by the labels, who have more bargaining power now that iTunes has caved.