Here's a slideshow about plastic bags, and the impact they have on our environment and our economy:
I've switched to the reusable bags that you find selling at most stores nowadays for $1, and...they are so much nicer! I love the big handles that I can put over my shoulder. I love that they're strong enough to hold two gallons of milk. I love that they are big enough that three of them hold a week's worth of groceries (well, that's if I don't put the milk in bags). I like the flat bottom that enables them to stand on their own when full of groceries. They're so much nicer, that I wonder why everyone doesn't use them all the time. Oh wait...maybe it's because they are always forgetting their bags at home, like I do. :) Seriously people [Mom], they cost a dollar; you should give them a try.
Note: the ones at Walmart for $1 don't have the hard bottom that makes them so much more supportive--so pick some up at Kroger or another store, where they still cost $1 but have the hard piece in the bottom.
Of course, the bags you find for $1 aren't exactly the ultimate in reusable bags--the best ones are the ones made of heavy-duty canvas, that you can run through the washing machine. But those are significantly more expensive...I've seen them at the farmer's market for $10. Maybe someday I'll be able to afford them. I bet they would last forever.
I hope that in my lifetime, plastic grocery bags will go extinct, so that the bags I crochet out of them will be a novelty item. Someday I'll tell the stories to my grandchildren. "Gather round, kids. Once upon a time, people brought their groceries home in these flimsy, ugly plastic bags. They hardly held anything, and wouldn't stay upright in your trunk, and sometimes they would rip and send your groceries rolling across the parking lot. And they had to put these warning labels on the sides, because sometimes babies would suffocate in them." "Eeeeewwww!" reply the kids. I can just see it, can't you?