카드 되나요?
kadeu doenayo?
Do you take cards?
Why this spelling
This romanisation is not the spelling copied letter by letter. It is built from the National Institute of Korean Language’s Revised Romanization, which writes what the word sounds like once the sounds next to each other have changed it.
When you would say it
Worth asking before the seller starts bagging things up rather than after.
How a market actually works
Markets are not a tourist activity with a fixed script; they are where a lot of people do their shopping. Which means the etiquette is ordinary shop etiquette, with two differences worth knowing in advance.
From the same chapter
Buying Things
Card number 47 of the book
The guidebook prints these as numbered cards, so you can hold up a number instead of trying to pronounce it. The Korean edition comes with it and has the same numbers in the same places.
See the guidebook