The difference between supermarkets here and ones in my country is: in Japan, the person behind the cash register doesn't do every single service for you. They mainly "only" count your shopping and receive payment from you. In some supermarkets they give you plastic bags for free without asking, but in some other, you have to ask for a plastic bag if you need one and they charge you 5 Yen. This is one of those ways to go green. Shopping bags that you can call eco bags or other names are popular in Japan. More and more people bring their own shopping bags to shop.
Gyoumu Suupaa is even generous enough to give free cardboard boxes if you need. Some genius must have had this idea, as otherwise, Gyoumu's management would have to deal with throwing away these boxes (garbage in Japan is regulated, in relation to recycle). So, it is a good idea to give away these cardboard boxes free to customers who need.