10pk 28" X 22" Poster Board White - Up & Up™ : Target
Amazon.com : 30 Pack White Foam Core Board 20 x 30 Inch Foam Core Backing Board Sheet 3/16 Inch Thickness Polystyrene Poster Board for Presentations, Signboards, Arts and Crafts, Framing, Display, Projects : Office Products
Amazon.com: BAZIC Poster Board 22" X 14" White Poster Board Paper for School Craft Project Presentation Drawing Graphic Display (3/Pack), 1-Pack : Everything Else