i have seen lots of instructions on line for totes knitted or crocheted from plastic bags

like
MagKnits, your friendly online knitting magazine
Marlo's Crochet Corner
CRAFTS : Needle Arts : Recycled-Plastic Carryall : DIY Network
http://www.ccthita-swan.org/pdf/Crocheting_bags.pdf
Pie and Coffee How to knit a plastic bag
Tote Bag = recycled Plastic Bags

doormat
My Recycled Bags.com Plastic Bag Doormat Rug

I think craftster had a tuts on ironing bags together to make a tote also
Extreme Plastic Bag Makeover (Img Heavy!!!)
also duct tape:
This IS a plastic bag! Recycled and very resuable! (Pictures of making of bag)

hth