We here at Create-NRG love our fabric bags and bring them with us anytime we do groceries or run errands. However, some people prefer plastic bags, which is fine, as long as you stick to the 3 Rs!
Make sure you really need a bag. Sometimes, you run to the store for just a thing or 2, that can easily be tossed into your purse or pocket or even just held in your hand until you get to your car. Other items that have handles (like jugs of milk or juice) or large bulk items (like packages of tissue paper or toilet paper) shouldn't be placed into bags since they can easily be carried without and there will most likely not be anymore room in the bag for anything else.
Plastic bags take up very little space. This means you can throw a few in your car, your pocket, your purse, your stroller, your little basket on your bike, or your backpack so that you will always have some available when you make an unplanned stop at the store. Other ways to reuse plastic bags include: