For Sandwich boards click here. For Banners click here. Sign material varies with each application and budget. Coroplast (corrogated plastic) is the least expensive. Comes in a variety of colors. Sintra is a smooth architectual plastic better for higher quality indoor signs. Intecel is a thick white plastic material suited to larger outdoor signage. Many other substrates available depending on your needs. Vinyl lettering material is available in standard colors or translucent for lighted signs.