Well, we have several bags that remain in our car now and we use those instead of plastic shopping bags. We bought them from Ikea for like 65 cents a piece and they hold an ENORMOUS amount of stuff!
We do not buy the individually packaged products...you know, those single serving snacks? Instead, we buy the larger bag, and give our dd her snacks in reusable storage containers (tupperware). We also do not use sandwich bags or ziploc bags for any reason...we use our tupperware.
These are two ways to be ecologically respsonsible without spending more money. We also own just one car and I either walk to work or my dh drops me off on his way to work. Dd goes to preschool in the same building as his office, so that makes it easy.
We recycle aluminum cans religiously, although it's very difficult to recycle anything else in our town. They have really made it a chore to do, so sometimes we get lazy and don't.