O'Neill Heidi Tank Top - Girls' - $6.79

You can't believe your mom is actually letting you go to a co-ed party. Ahhh! Good thing you have the O'Neill Girls' Heidi Tank Top to wear, otherwise you would be totally freaking out. The Heidi's adjustable straps give you a just-right fit (phew!), while it's cute cut shows you have class. - $6.79