Hilary Duff has sold the most albums out of the current generation of Disney music stars. According to Billboard, Hilary has sold 8.3 million albums in the United States. This might be an unfair comparison since nobody buys CDs anymore, but it's nice to see Hilary on the top of this list.
Note: The Miley Cyrus number does not include Hannah Montana soundtracks. If it did, I assume Miley would be close to Hilary's number.
8,300,000 - Hilary Duff
4,414,000 - Jonas Brothers
3,333,000 - Miley Cyrus
1,354,000 - Selena Gomez (& the Scene)
968,000 - Demi Lovato
719,000 - Vanessa Hudgens
566,000 - Ashley Tisdale