Just say no. Buying a single lemon or bottle of aspirin? Do you really need a bag to carry it in?
Use it again. Reuse the produce bag you got at the store for last week's lettuce to hold this week's arugula. And the bag your bread comes in is the perfect size to carry a sandwich for lunch at work.
Choose something biodegradable. Wrap your food in paper instead of a plastic bag.
BYO grocery bags. Some stores offer incentives to shoppers who bring their own bags - a nickel back, or a chance to win a $25 store gift card. Make a habit of remembering your bags by hanging them on the doorknob as soon as they're emptied, then store them in your purse or car.
Take a tote. Reusable bags aren't just good for groceries. You can use canvas or other totes for clothes and holiday shopping, too.
Double up. Why take a plastic bag from Macy's when there's still room in that Target sack? You don't need to get a fresh bag from every store.
Reuse for Rover. When picking up after your dog, use something that's headed for the landfill anyway.
Don't toss good bags in the trash. Instead of buying kitchen garbage bags, reuse the bags that you already have. And remember to recycle what you can't use. Even the wrapping from dry-cleaned clothing can be slipped into grocery stores' plastics recycling bins.
Buy BioBags. Sold at natural-foods stores, BioBags work like plastic bags, but they're not made from petroleum and are biodegradable.