Top 10 best-selling ‘American Idols’ | LOS ANGELES - Over its eight seasons, “American Idol” has turned dozens of amateur singers into superstars. Kelly Clarkson went from blushing 20-something with a big voice to international sensation thanks to her top spot on the show, while the quiet but commanding Carrie Underwood scored Grammys, country music accolades and millions of album sales after winning the crown.