Dakota had this good idea about how to reuse those inflated plastic bags that are used to fill shipping boxes these days. We use them as poop bags to pick up after Nigel the dog. Basically, you can just cut off one end of the bag to deflate it, and then it's a nice, small bag for picking up poop. I guess this wouldn't work if you have a large dog, but they are the perfect size for our needs.
I went on the website for the inflatable shipping bag manufacturer, and they claim you can recycle the bags as #4 plastic, but I have some doubts about that.
When we're not recycling shipping bags or vegetable bags to pick up Nigel's "business," I use this brand called Oops I Pooped. They are biodegradeable dog poop bags. They work well and come in a nice compact pack of 80 or so bags. I'm not a big fan of the name, but what can I do?
another thing you can do is take packing materials to those smaller mom and pop shipping places (I take mine to the same place I have my P.O. Box) and they will reuse them....I've taken the inflatable bags to them and they said they would reuse them.