There are two things I have noticed here in Italy that would probably be a good practice in the United States, both deal with when you go shopping at grocery stores. If you want a bag to carry your groceries home you will pay an extra 5 centesimi per bag and then you must bag the groceries yourself. This practice encourages people to re-use bags as well as bring their own rolling cart or canvas bag. It is a common sight to see older ladies pulling their little cart along the streets in the morning after collecting their groceries for the day.
To use a grocery cart at the big stores you have to deposit either a 1 or 2 Euro coin. The carts are held together by short chains which require you to insert the coin to release the chain. To get your coin back you have to return the cart and reinsert the chain, and then coin pops back out. This insures that there are not carts left out amongst cars by lazy shoppers or along the side of the road.