The Girl With 500 Middle Names by Margaret Peterson Haddix

Disgusted by her daughter's run down school, Janie's Mother decides to move the family across town, giving Janie the opportunity to go to a better school. The family economy, fueled by hand knitted sweaters, falls apart when a shop owner decides to outsource to a cheaper foreign country for the sweaters. Janie, needing new clothes and wanting to protect her mother decides to start wearing the unpurchased sweaters, each with a different name on them. For a while, she claims that she has many different middle names. This fuels a 'run' for the name sweaters, especially those with the girls middle names on them.