Bags aren't free here

No free plastic bags.
Buy a paper bag at the counter, or take items by hand.

No free bags.
Reusable bags sold near checkout (~₩500-1,500).

Plastic bags banned since 2022.
Small bread bags still free.

Disposable cup ban rolling out.
Expect a deposit or BYO cup discount.

Plastic bags still allowed.
Many vendors will hand them out.

Anything that crushes into a pocket works.
Convenience-store "market bags" cost ~₩1,500 if you forget yours, but the cute Korean illustrated totes at Daiso are ₩2,000-5,000 and double as a souvenir.

A 100-won coin solves the convenience-store paper-bag problem and tips a market vendor for a free bag swap.
T-money cards work too.

Starbucks, Twosome, and most cafés give a ₩300-400 discount for tumblers.
Some chains will fill any clean cup you bring.

Trash bags are different.
Korea uses district-specific paid jongnyangje bags for trash.
Don't confuse them with shopping bags.

Recycling is enforced.
Most accommodations sort plastic, paper, food waste, and general.
Your host will usually post a guide.

Daiso has the cheapest cute totes.
The Korean-illustrated foldable ones are ₩2,000-5,000 and pack into a cosmetic pouch.
Souvenir + utility.