Selfsufficientish.com

I know there will be a thread on here already, but i can't find it
over here is you go to a particular supermarket, they chuck a load f carrier bags at you to pack your shopping in, whether you ask for them or not, usually there are too many anyway, so you end up with several unused ones
these clean unused one are great for making burgers
cut the handes and the bottom off the bag, straighten out and cut into squares, then when you are pressing your burgers use one each side so that it doesn't stick, also great for freezing

using an iron and a coupple of sheets of paper iron plastic bags togeather to make sheeting to use as a tarp, raincoat, bags or WHU.
Use minimum heat that still seals the bags together. paper under and paper on top of the plastic. unprinted bags work best. - the thin supermarket ones.

those who will attack me RE:plastic fumes and toxicity - i say i cant smell it and am not worried (burning plastic, now thats another story ) if you are concerned then do it outdoors/well ventilated.

is a very versatile technique though, and makes things good and water tight. think pack liners, cammel packs (not sure about supermarket bag food safe toxicity though)