The best way to buy food is at your local farmer's market or local independent shops, or through a box scheme, where the food isn't shrink-wrapped to within an inch of its life, and we can put it in reusable bags we've brought with us. Pick foods that have a relatively low level of packaging. If you're buying apples for example, pick the loose ones to put into a bag yourself (you could even take bags with you for this purpose). Don't tie up the top too tightly: you can reuse it then. This question was asked on the wiki: WorldHealer.