Everything nowadays is individually wrapped. Think of all that packaging in the dumps...! When you shop, think about buying bulk and passing on the individually wrapped items. Or buy bagged items instead of plastic. Or, ask yourself "What can I reuse around my house?"
You can keep them in your car trunk. Paul bought me 8 for Christmas. This is something simple that will save waste and unneeded plastic. This doesn't mean that you shouldn't ever take a plastic bag home with you...afterall, if you have some they're great to use around the house (like bathroom trash liners).
DIAPER PAIL LINER
I bought a cute one on blueberries.com that you can wash when you wash your laundry (obviously I do cloth diapers, so you may not need this suggestion).
It doesn't hurt to give a quick rinse to your sandwich bags and such. I do throw out the ones we use to hold the cheese blocks though...because there's more chance for mold growth. But chips, sandwiches, etc., it makes sense. I'd try to stay away from one-use containers...they're a waste and fill up landfills like crazy.
Why? Why not use a lunch pail or the newer titanium or steel pails. I have a plastic sandwhich container I use for my sandwiches (of course it's plastic).
There's so much stuff you can buy that come in cool containers you can use again. We reuse containers of nuts for holding rice, flour, snacks, candy, etc. and just label what they are and when we put it in there. We also fill up old little spice containers with some of the seasonings from large bulk containers.
I always save my gift wrapping and ribbons. It's helped a ton when I just need something to tie onto a goody plate so it looks better. Tissue paper is really helpful for that too.
I have used an old dress, shirt, table cloth and wash rags to make some fun little pillows and baby toys and also a wall hanging. Sometimes you can get great creations from a cool material or pattern you have laying around the house. Plus, it's definitely cheaper.