A (disposable) shopping bag provided at the cash register; usually refers to plastic carrier bags.
最近、レジ袋が有料になったスーパーが増えた。
Recently more supermarkets have started charging for plastic bags.
エコバッグを持って行けばレジ袋を断れる。
If you bring an eco-bag, you can refuse a plastic bag.
レジ袋は薄くて破れやすいので注意してください。
Be careful because plastic shopping bags are thin and tear easily.