Amazon.com: Mega Format Expanded PVC Plastic Sheets - 8" X 10" Rigid White Sheet for Crafts, Signage, & Displays - Sintra, Celtec PVC Board - Waterproof for Outdoors Use - 1/8" 3mm
Pacon Craft Plastic Art Sheets, 11 X 17 Inches, Assorted Colors, Set Of 8 : Target
Cut to Size, Polycarbonate & Acrylic Plastics : TAP Plastics
Polycarbonate and Plastic Sheeting Ideas - The Home Depot