Some old pop songs like Mandy Moore, Hilary Duff, Lindsay Lohan songs?

Try artists like Avril Lavigne, Kelly Clarkson, and Colbie Caillat (their first album or so of course because their music style changes over time, especially Avril. Avril Lavigne and Kelly Clarkson's first albums had a more soft rock than pop sound, which I think is what you're asking for) You can go on youtube and check out some of their popular songs and you might even like some of their newer hits as well. Do yourself a favor and stay away from those crappy artists like Lady Gaga.