Complex sentence: Paige was a model/actress who, since the age of 3, was seen on magazine covers and billboards, was also the box model of many toy boxes such as Barbie, Polly Pocket, Britney Spears Doll products and Pound Puppies.
Split into simpler sentences: Paige was a model/actress who, since the age of 3, was seen on magazine covers and billboards. Her photos were also used on many toy boxes such as Barbie, Polly Pocket, Britney Spears Doll products and Pound Puppies.