Plastic, when used once and thrown away, isn't very green. Plastic that you can reuse again and again is eco-excellent. Crafted in lightweight, waterproof polyester, the Envirosax Graphic Series ($8.50, Envirosax.com) has reinforced seams to hold the equivalent of two ordinary grocery bags. Standout patterns: The Animal Planet blue-eyed kitty and the many shades-of-green flora in the Botanica series.